Taxonomic Synopsis of the Genus Desmodium Sensu Lato (Fabaceae, Desmodieae) in Nigeria

Abstract

The Desmodium group is one of the three groups in the tribe Desmodieae distinguished by their lomentaceous fruits, trifoliolate leaves, presence of stipels, and hooked hairs. Due to recent generic circumscription in the Desmodium group, a taxonomic synopsis of the Nigerian members of Desmodium s.l. is presented, including an updated checklist, diagnostic characters, morphological descriptions, and distribution records. The Nigerian taxa of the Desmodium s.l. comprise six genera and nineteen species, of which six species are insufficiently known. Grona and Desmodium each include seven species, while Pleurolobus includes two species. The genera Sohmaea, Polhillides, and Hylodesmum are each represented by a single species. This synopsis aims to consolidate the available taxonomic information on the nineteen species and provide a foundation for future studies on the taxonomic revision, diversity, ecology, and conservation of the tribe Desmodieae in Nigeria.

1. Introduction

Desmodieae (Benth.) Hutch. is one of the most evolutionarily advanced tribes in the subfamily Papilionoideae, due to its high level of morphological specialization, particularly in its fruit and flower structures [1]. The tribe has a pantropical distribution and consists of two subtribes, Desmodiinae and Lespedezinae, comprising approximately 530 species distributed among 32 genera worldwide, mostly in tropical and subtropical regions [2,3]. Based on molecular phylogenetic data, the tribe is further divided into three monophyletic subgroups, i.e., Lespedeza Michx., Phyllodium Desv., and Desmodium Desv. [4]. The presence of indehiscent legumes is diagnostic for the species in Lespedeza group, while dehiscent legumes with indehiscent loments characterize the Desmodium group [5]. The Desmodium group is the most diverse and prominent, comprising 26 genera and 3 subgenera, namely Desmodium, Acanthocladum Pedley, and Sagotia (Duchass. & Walpers) Baker [6]. However, the genus Desmodium, being the core genus in the Desmodium group, is polyphyletic, making it both controversial and taxonomically problematic [5,7,8,9].

Previously, 39 species of Desmodium were recognized in Africa [10], and 17 species were reported in Nigeria, based on a recent account by Bello et al. [11]. Due to the polyphyletic nature of the genus and recent phylogenetic evidence that led to a new generic classification, the African species of Desmodium are now divided into nine genera, six of which include species found in Nigeria [12].

The documentation of plant species occurrence and diversity in Nigeria has been an ongoing effort. Taxonomists in the country have largely relied on the three volumes of Flora of West Tropical Africa by Hutchinson and Dalziel and Trees in Nigeria by Keay [13,14,15,16,17,18]. Although these two publications are comprehensive and fairly illustrated, they are outdated and unwieldy. Many Nigerian taxa are either not represented or have not been revised using the current, updated classification systems [19]. Our aim in this study is to provide a taxonomic synopsis of the Nigerian members of Desmodium s.l. This includes nomenclatural updates, diagnostic characters, distribution records, and artificial dichotomous keys to the species of the newly segregated genera of Desmodium s.l.

2. Materials and Methods

This taxonomic synopsis is based on fieldwork in Nigeria, an extensive survey of the literature, and an examination of herbarium specimens of Desmodium species s.l housed in the Nigerian National Herbarium, FHI, IFE, UIH (UCI) (acronyms according to Thiers [20]). The plant specimens collected in the field were deposited in the IFE Herbarium. Online platforms such as JSTOR https://plants.jstor.org (accessed 21 March 2025), the International Plant Names Index https://www.ipni.org (accessed 21 March 2025), Tropicos https://www.tropicos.org/home (accessed 21 March 2025), and other online herbaria where type specimens were available were used to sort out the nomenclature and study the type specimens. Qualitative morphological character observations were carried out using a stereomicroscope with an attached camera lucida to draw the floral structures, while a metric ruler was used for measuring the quantitative characters. The mature flowers were dissected and placed in glycerol on a microscopic slide for observation after being rehydrated in hot water for an hour. Data collected from morphological studies and fieldwork were used to describe the species and construct the keys.

3. Results and Discussion

3.1. Key to the Genera of Desmodium s.l. in Nigeria

• 1a. Loments segmented, with distinct constrictions between articles; stipels present at leaflet bases .............................................................................................................................2
• 1b. Loments not distinctly segmented; stipels absent.............................................................................................................................................................................................................4
• 2a. Stamens diadelphous; hairs on loments hooked or uncinate...........................................................................................................................................................................................3
• 2b. Stamens monadelphous; loments with straight or appressed hairs..............................................................................................................................................................Hylodesmum
• 3a. Loments with uncinate hairs on margins and/or surface; leaflets always trifoliolate...................................................................................................................................Desmodium
• 3b. Loments with hooked hairs only on margins; leaflets uni- or trifoliolate...............................................................................................................................................................Grona
• 4a. Calyx lobes subequal; flowers in short racemes or fascicles..............................................................................................................................................................................Polhillides
• 4b. Calyx lobes unequal; flowers in elongated racemes or terminal inflorescences............................................................................................................................................................5
• 5a. Fruits indehiscent, flattened or inflated; inflorescences terminal; bracteoles persistent..............................................................................................................................Pleurolobus
• 5b. Loments with 2–4 articles; inflorescences terminal or axillary; bracteoles caducous........................................................................................................................................Sohmaea

3.2. Grona Lour.

Grona Lour., Fl. Cochinch. 2: 459. 1790. Type species: Grona heterocarpos (L.) H.Ohashi & K.Ohashi. (=Grona repens Lour.).

Perrottetia DC., in Ann. Sci. Nat. 4: 95. Jan. 1825, nom. illeg., non Kunth (1824). Type species: Perrottetia barbata (L.) DC.

Nicolsonia DC., Prodr. 2: 325. mid Nov. 1825 [substitute name for Perrottetia DC. 1825, non Kunth 1824]; Mem. Leg. 7: 311, t. 51. 1826; Schindl., in Repert. Spec. Nov. Regni Veg. 23: 357, adnot. 1927. Type species: Nicolsonia barbata (L.) DC. Nicholsonia Span., Companion Bot. Mag. 1: 346. 1836, sphalm. ut ‘Nicholsonia oxalidifolia Span.’

Sagotia Duchass. & Walp., in Linnaea 23: 737. 1851 [Type species: Sagotia triflora (L.) Duchass. & Walp.], nom. rej. vs. Sagotia Baill. [Euphorbiaceae], in Adansonia 1: 53. 1860, nom. cons.

Desmodium sect. Sagotia (Duchass. & Walp.) Benth., Miq. Pl. Jungh. 2: 222, adnot. 1852; Benth., in Benth. & Hook. f., Gen. Pl. 1: 520. 1865; H.Ohashi, in Ginkgoana 1: 233. 1973; Pedley, in Austrobaileya 5: 227. 1999.—[Meibomia sect. Sagotia (Walp.) Kuntze in Post, Lex. Gen. Phan. 357. 1903, nom. nud.].

Desmodium sect. Nicolsonia (DC.) Benth., in Miq., Pl. Jungh. 2: 222 1852; Benth., in Benth. & Hook. f., Gen. Pl. 520. 1865; H.Ohashi, in Ginkgoana 1: 196. 1973; Pedley, in Austrobaileya 5: 227. 1999.—[Meibomia sect. Nicolsonia (DC.) Kuntze in Post, Lex. Gen. Phan. 356. 1903, nom. nud.].

Desmodium subgen. Sagotia (Duchass. & Walp.) Baker, in Hook. f., Fl. Brit. India 2: 173 1876); H.Ohashi, in Ginkgoana 1: 166. 1973; Pedley, in Austrobaileya 5: 226. 1999.

Subshrubs or herbs, sometimes shrubs. Leaves alternate, simple or trifoliolate, petiolate, stipulate; stipules free, persistent or caducous; leaflets chartaceous or subcoriaceous, petiolulate, stipellate; apex rounded, obtuse or emarginate; base rounded or cuneate; margins entire; stipels subulate. Inflorescences in axillary and/or terminal racemes, occasionally in panicled cymes; primary bracts persistent or caducous; secondary bracts when (rarely) present, usually depauperate; bracteoles absent; pedicel present; flowers pedicellate, lax or dense. Calyx campanulate, 5-lobed, bilabiate. Standard obovate to orbicular, usually rounded or retuse; Wing petals oblong to hatchet-shaped, often auriculate. Keel petals triangular, scythe-shaped, or deltoid, usually long-clawed. Stamens diadelphous, vexillary stamen free. Ovary sessile without disk around the base. Loments sessile or stipitate, more than 3-jointed, adaxial suture more or less thickened, continuous or slightly constricted between articles; articles small-sized, abaxial suture slightly or distinctly constricted, hooked-hairy on lateral surfaces. Stamens 10, dialdelphous.

Species in Nigeria

G. adscendens (Sw.) H.Ohashi & K.Ohashi

G. barbata (L.) H.Ohashi & K.Ohashi

G. hirta (Guill. & Perr.) H.Ohashi & K.Ohashi

G. ramosissima (G. Don) H.Ohashi & K.Ohashi

G. setigera (E.Mey) H.Ohashi & K.Ohashi

G. triflora (L.) H.Ohashi & K.Ohashi

G. schweinfurthii (Schindl.) H.Ohashi & K.Ohashi (insufficiently known).

Key to the species

• 1a. Plant erect or ascending, stems not rooting at the nodes.................................................................................................................................................................................................2
• 1b. Plant creeping, prostrate, trailing, or scrambling; stems rooting at the nodes .............................................................................................................................................................3
• 2a. Leaflets orbicular-oval to lanceolate; flowers in dense clusters, pink to mauve………...............................................................................................................................G. barbata
• 2b. Leaflets narrowly obovate to oblong-elliptic; flowers solitary or in pairs, reddish to purple with white tinge..............................................................................G. ramosissima
• 3a. Stoloniferous herb; inflorescences axillary raceme only..................................................................................................................................................................................G. triflora
• 3b. Non-stoloniferous herb; inflorescences terminal and axillary raceme..........................................................................................................................................................................4
• 4a. simple or trifoliolate leaf; articles scarcely separating, dehiscing as a whole along the lower suture...........................................................................................................G. hirta
• 4b. Leaves always trifoliolate; articles separating and not dehiscing .................................................................................................................................................................................5
• 5a. Stems patently hirsute or setose with spreading silky hairs; stipules scarious, lanceolate, 2–3 mm long; appressedly pilose on both sides .....................................G. setigera
• 5b. Stems with white, appressed to spreading hairs; stipules ovate to lanceolate, 4–8 mm long; leaflet glabrous above, densely appressed pilose beneath...........G. adscendens

G. adscendens (Sw.) H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(2): 108. 2018. Hedysarum adscendens Sw., Prodr. [O. P. Swartz] 106. 1788; Fl. Ind. Occ. 3: 1263. 1806. Desmodium adscendens (Sw.) DC., Podr. [A. P. de Candolle] 2: 332. 1825; B. G. Schub., in Fl. Trop. E Afr. Legum. 3, Papil. 1: 461. 1971; H.Ohashi, in Ginkgoana 1: 199. 1973; Pedley, in Dassaanayake, Rev. Handb. Fl. Ceylon 10: 180. 1996; B. G. Schub., in Ann. Missouri. Bot. Gard. 67: 627. 1980; Du Puy & Labat, Leg. Madag 611. 2002; Lima & al., in Phytotaxa 169(1): 17. 2014. Meibomia adscendens (Sw.) Kuntze., Revis. Gen. Pl. 1: 195. 1891. Type: Jamaica, “Ind. Occ.”, without date, Swartz s.n. (Lectotype: S barcode S-R-2772 [web!]; isolectotype: B barcode B-WILLD13792-01 [web!], designated by Schubert [21].

Perennial herb or undershrub, creeping, climbing, trailing, or prostrate, with straggling, grey-haired stems extending up to 1 m. Stems cylindrical, rooting at nodes, surface covered with white, appressed to spreading hairs. Leaves trifoliolate; stipules persistent, brown, ovate-lanceolate, puberulent to pilose or glabrescent, 4–8 × 1–3 mm; petiole pilose, 10–35 mm long; leaflets obovate; apex emarginate, base obtuse; glabrous above, densely appressed pilose beneath; 11–46 × 8–36 mm. Inflorescences axillary or terminal racemes; flowers purple, pinkish-red, or whitish-blue; pedicels pubescent, 5–20 mm long; primary bracts deciduous, ovate, ciliate, puberulent to pilose, subtending two pedicels, 3–6 × 1–2.5 mm; secondary bracts absent. Calyx 5-lobed, bilabiate, puberulent; lobes with pilose teeth, lobes 1.5–4 mm long. Standard obovate, short-clawed, 4.5–9 × 2–5 mm. Wing petals oblong, auriculate, short-clawed, 2–3.5 × 1–2 mm. Keel petals triangular, truncate at apex. Loment with a stipe 0.5–2 mm. Long, indehiscent, hairy, sticky, 2–5-articled, 9–25 × 1.5–3.5 mm; articles slightly indented on one side, upper suture straight, lower suture sinuate.

Phenology: Flowering and fruiting throughout the year.

Diagnostic characters: G. adscendens is similar to both G. hirta and G. triflora in growth habit and leaflet shape, but can be easily distinguished by its stipules, which are ovate-lanceolate compared to ovate-attenuate in G. hirta and obliquely ovate in G. triflora. It can be characterized by having the largest standard among the species in the genus, 4.5–9 × 2–5 mm, and leaflets that are dark green (Figure 1A) above and pale green beneath.

Distribution: Grona adscendens is distributed in North-West, South-West, South-South, and South-East Nigeria.

Additional specimens examined: NORTH-WEST NIGERIA: Kaduna State: Zaria-Kaduna Road, 6 March 1978, Ekwuno 160 (FHI). SOUTH-WEST NIGERIA. Ekiti State: Addo-Ido Road, 21 July 1954, Lowe 12 (UIH). Lagos State: Lekki Conservation Centre, 19 March 1992, Lowe 38 (UIH). Ogun State: Olokomeji Forest Reserve, 5 January 1980, Fagbemi 24 (FHI); Olaparun, 6 June 1969, Gbile 24 (FHI); Omo Forest Reserve, 17 June 1991, Ekwuno 296 (FHI). Ondo State: High forest Iwaro-Oka, 19 June 1978, Olorunfemi 25 (FHI); Oluwa Forest Reserve, 14 November 1980, Ekwuno 26 (FHI). Osun State: Univ. of Ife Agric Farm, 31 July 1973, Olorunfemi 27 (IFE); Univ. of Ife Agric Farm, 1 August 1973, Akabogu 28 (IFE); Univ. of Ife Agric Farm, 21 August 1973, Akabogu 146 (IFE); Univ. of Ife campus, 16 October 1970, Adewole 98 (IFE); Univ. of Ife campus, 15 December 1969, Lufadeju 27 (IFE); Univ. of Ife campus, 2 May 1969, Ogunyemi 52 (IFE); Erin-Odo, 7 April 1968, Hill 965 (UIH). Oyo State: Sapoda Forest Reserve, 6 September 1974, Olorunfemi (FHI); Forestry headquarters, 2 March 1973, Daramola 268 (FHI); Federal Agric. Quarter M.P., 18 December 1969, Adewole 46 (IFE); Forestry headquarters, 2 March 1973, Daramola 268 (FHI); Federal Agric. Quarter M.P, 18 December 1969, Adewole 46 (IFE); Iseyin, May 1966, Guile 782 (IFE); West bank of lake IITA, 14 December 1991, Lowe 4691 (UIH); Ibadan-Oyo road, 13 April 1971, Lowe 35 (UIH); Ibadan, 8 July 1980, Lowe 24 (UIH). SOUTH-EAST NIGERIA: Imo State: Bendel Forest Reserve, 31 December 1981, Ekwuno 430 (FHI). SOUTH-SOUTH NIGERIA. Cross-River State: Edondon farmland, 15 May 1978, Jagunwigbon 15 (FHI); Awi Forest Reserve, 16 October 1978, Ekwuno 289 (FHI). Awi Forest Reserve, 9 December 1981, Ekwuno 610 (FHI); Awi Forest Reserve, 19 October 1978, Ekwuno 315 (FHI); Oban Group East Forest Reserve, 11 October 1972, Daramola 117 (FHI); 3628 Sapoda, May 1966, Guile 783 (IFE); Itekpa stream bank bekwarra, 13 February 1980, Inah 72 (UIH). Delta State: Odimod near Forcados, 4 June 1992, Lowe 10 (UIH). Edo State: Sapoda Forest Reserve, 26 August 1981, Ekwuno 31 (FHI); Inv. 273 Ugo, 14 January 1980, Ekwuno 79 (FHI); Iguoziakhi Forest Reserve, 12 March 1979, Ekwuno 113 (FHI); Atuagbo Forest Reserve, 19 January 1982, Ekwuno 162 (FHI); Benin, 29 April 1965, Lowe 767 (UIH); River Jameson Sapoda, 16 February 1967, Lowe 1090 (UIH). Rivers State: Yenogoa area, 02 Jan 1970, Lowe 13 (UIH); Oporoma Southern Ijo, 20 December 1972, Lowe 193 (UIH).

G. barbata (L.) H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(2): 109. 2018. Hedysarum barbatum L. in Syst. Nat., ed. 10. 2: 1170. 1759. Nicolsonia barbata (L.) DC., in Prodr. [A. P. de Candolle] 2: 325. 1825. Perrottetia barbata (L.) DC., in Ann. Sci. Nat. (Paris) 4: 96. 1825. Urania barbarta (L.) Desv., in Mem. Soc. Linn. Paris 4: 309. 1826. Meibomia barbata (L.) Kuntze, in Rev. Gen. Pl. 1: 195. 1891. Desmodium barbatum (L.) Benth, in Pl. Jungh. [Miquel] 2: 224. 1852. Type: “Habitat in Jamaica”, without date, Herb. Linn. No 921.48 [lectotype: HL Barcode LINN-HL921-48 [Web!], designated by Schubert [22].

Perennial or annual herb, variable in form, ranging from short-lived procumbent forms to erect, woody, branched herbs or undershrubs, up to 1.2 m or more in height. Stems greyish or deep purple, densely tomentose or with appressed to spreading pilosity. Leaves simple or trifoliolate; stipules conspicuous and persistent, ciliate, deltoid-attenuate, 3.5–8 × 0.5–2 mm, pilose to glabrescent on outer surface; petiole 3–19 mm long; leaflets orbicular-oval to lanceolate, 12–47 × 6–20 mm, rounded at apex and base; upper surface green and glabrous, lower surface pale green with prominent silky hairs. Inflorescences terminal and axillary, densely flowered racemes, 15–69 mm long; flowers small, pink, red, pale purple, or mauve usually tinged with white, hairy, borne in clusters; pedicels uncinulate-pilosulous, 3.5–9 mm long; primary bracts persistent, ovate-acuminate, 5–7 × 1.5–2 mm, ciliate, pilose to glabrescent each subtending 2 pedicels; secondary bracts when (rarely) present usually inconspicuous. Calyx pale green, 5-lobed, silky pilose, 2–5 mm long. Standard obovate, somewhat clawed, 2.5–3.5 × 1–2.5 mm. Wing petals oblong, obtuse or short-clawed, 3–4.5 × 0.5–2 mm. Keel petals truncate at apex, long-clawed. Loment sessile to shortly stipitate, pubescent on the surface, with sticky hairs, 2–3.5 × 2–3 mm, 1–6 articled; articles partially separating, then dehiscing along the lower suture.

Phenology: Flowers from October to November.

Diagnostic characters: G. barbata has a similar habit to that of G. ramosissima but can easily be distinguished by leaflet shape, which is orbicular-oval to lanceolate vs. narrowly obovate to oblong-elliptic in G. ramosissima. It is also similar to G. ramosissima in terms of its inflorescence type, but can be distinguished by its size, 1.50–6.90 cm long vs. 6.80–18.20 cm long in G. ramosissima, and by its densely congested inflorescence (Figure 1C) versus lax inflorescence in G. ramosissima (Figure 1D). The stem is tomentose or appressed to spreading pilosity.

Distribution: G. barbata occurs in Erin-Ile, Ilorin, Jos, and Mokwa in North Central Nigeria; Zaria and Afaka in North-West Nigeria; Ibadan in South-West Nigeria; and Auchi in South-South Nigeria.

Additional specimens examined: NORTH-WEST NIGERIA: Kaduna State: Afaka Forest reserve, 4 March 1959, Stanfield 25 (FHI); North of Zaria, 2 October 1964, Latilo 116 (FHI); Ribako Forest Reserve, 19 November 1962, Latilo 454 (FHI); Shika Zaria Province, 12 May 1966, Latilo 30 (FHI); Near sewage samaru Zaria, 19 Aug 1970, Olorunfemi 1004 (FHI); Him Forest Reserve, 4 March 1959, Stanfield 240 (FHI). NORTH CENTRAL NIGERIA: Plateau State: South Side of Forest School Jos, 20 November 1982, Latilo 20 (FHI); Ray Field Jos, 25 August 1973, Greenhall 535 (UIH); Mining field Jos, 25 July 1963, Olorunfemi 78 (UIH). Niger State: Bida-Mokwa road, 28 July 1970, Lowe 22 (UIH); Bida-Mokwa, 12 January 1971, Lowe 219 (UIH). SOUTH-WEST NIGERIA. Oyo State: Fed. Agric. Quarters MP, 25 November 1969, Adewole 57 (IFE); Moor Plantation, 25 November 1968, Ogunyemi 5 (IFE). SOUTH-SOUTH NIGERIA: Edo State: Auchi, 31 October 1969, Lowe 11795 (IFE); Igara-Auchi, 31 October 1969, Lowe 1885 (UIH).

G. hirta (Guill. & Perr.) H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(2): 114. 2018. Desmodium hirtum Guill. & Perr., in Fl. Seneg. Tent.: 209. 1832; Schub. in Bull. Jard. Bot. État Bruxelles 22: 287, 288. 1952 & Fl. Congo Belge et Ruanda-Urundi. 5: 186, fig. 11/B 1954; Hepper, in Fl. W. Trop. Afr., ed. 2 [Hutchinson & Dalziel] 1: 585. 1958. Meibomia hirta (Guill. & Perr.) Kuntze, in Revis. Gen. Pl. 1: 198. 1891. Type: Senegal, without date, Perrottet 247 (isosyntype: BM Barcode BM000842729 [Web!], fide Schubert [22].

Perennial herb, creeping and spreading over bare ground, occasionally scrambling into the lower parts of grass clumps, especially in lightly grazed areas. Stems red, wiry, pubescent, with laxly spreading pilose hairs, arising from a somewhat tuberous taproot; stems up to 1.2 m long. Leaves simple or trifoliolate; stipules brown, ovate-attenuate, 2–6 × 1.5–2.5 mm, glabrous to sparsely pilose; petiole 3–14 mm long, spreading pilose; leaflets obovate, 9–38 × 4–24 mm, apex truncate or slightly emarginate, base rounded or wedge-shaped; appressed pilose on both surfaces or nearly glabrous. Inflorescences lax, axillary and terminal racemes, sometimes arranged in a panicled cyme, 15–91 mm long; flowers pale pink to deep rose or purple; pedicels slender, 6–12.5 mm long, puberulent; primary bracts ovate-attenuate, 2–6 × 1–2.5 mm, pilose to glabrous, long-ciliate; secondary bracts and bracteoles absent. Calyx puberulent, both lips pilose. Standard obovate, obtuse at apex, narrowed at base. Wing petals hatchet-shaped, clawed. Keel petals deltoid, clawed. Loment sessile to shortly stipitate, 6–10 × 2–3.5 mm, indented on one side, 3–7-articled; article partially separating from each other, then dehiscing as a whole along the lower suture.

Phenology: Flowers from January to May.

Diagnostic characters: Grona hirta is a quadrangular creeping herb (20–30 cm high) spreading over bare ground between grazed down grass tussocks with stems pubescent to laxly spreading pilose. It can be characterized by its almost glabrous leaflets.

Distribution: The species occurs in all six geopolitical zones, with the exception of South-East Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA. Adamawa State: Gombi Road, 12 March 1982, Odewo 69 (FHI). Taraba State: Mambilla plateau, 10 April 1972, Daramola 91 (FHI); Gembu area, 12 February 1976, Ekwuno 211 (FHI); Gembu, 12 January 1976, Ekwuno 288 (FHI); Maisamari, 19 January 1975, Ekwuno 141 (FHI). NORTH-WEST NIGERIA: Kano State: Koto town, Ogbile road, 20 August 1983, Olorunfemi 26 (FHI); Bakwa village, 8 March 1973, Lowe 128 (UIH). Kastina State: Daura, 12 October 1970, Jackson 31 (UIH); Daura, 21 October 1970, Jackson 21 (UIH). Zamfara State: Gusau, 14 September 1970, Lowe 23 (UIH); Gusau, 14 September 1970, Lowe 54 (UIH); South Gusau, 17 June 1970, Lowe 39 (UIH); South Gusau, 17 June 1970, Jackson 12233 (IFE). NORTH CENTRAL NIGERIA: Kwara State: Open grassland, 9 December 1970, Gbile 1425 (FHI). Plateau State: Sardauna province, 28 December 1973, Chapman 3284 (FHI). SOUTH-SOUTH NIGERIA: Cross-River: Oban West Forest Reserve, 10 October 1972, Daramola 201 (FHI); Iyanmtta, 12 September 1981, Ekwuno 648 (FHI). SOUTH-WEST NIGERIA. Osun State: Univ. of Ife campus, 6 September 2013, Ibhanesebhor 114 (IFE); Univ. of Ife campus, 1 January 1968, Sanford 6991(IFE). Oyo State: Igbetti, 29 December 1966, Stanfield 89 (FHI); Igbetti, 21 October 1964, Stanfield 24 (FHI); Bodija Ibadan, 17 June 1970, Lowe 27 (UIH).

G. ramosissima (G. Don) H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(2): 115. 2018. Desmodium ramosissimum G. Don, in Gen. Hist. 2: 294. 1832; Schub., in Bull. Jard. Bot. Brux. 22 (3/4): 293. 1952 & in Fl. Congo Belge et Ruanda-Urundi. 5: 191. 1954; Hepper in Fl. W. Trop Afr., ed. 2 [Hutchinson & Dalziel] 1: 584. 1958. Type: St Thomas [S. Tomè], without date, G. Don s.n. [Holotype: BM Barcode BM000842722 [n.v.], fide Schubert [22,23].

Perennial herb or undershrub, erect, slightly woody, growing up to 1.8 m tall or sometimes as small as 0.24 m; occasionally shrubby. Stems brown or pink, densely strigose, with slender, spreading branches bearing appressed hairs; root system nodulated. Leaves trifoliolate; stipules obliquely lanceolate to attenuate, 2–5.5 × 1–2.5 mm, strigose at base, glabrous to puberulent, and ciliate; leaflets narrowly obovate to oblong-elliptic, 12–32 × 6–14 mm, apex and base rounded; upper surface dull green and glabrous; lower surface pale green, with appressed pilose indumentum and prominently pinnate venation; petiole 4–18 mm long, abundantly strigose. Inflorescences lax terminal axillary racemes, small, 68–182 mm long; flowers purple, pink, or red with a white tinge, solitary or in pairs; pedicels 4–15 mm long, strigose; primary bracts each subtending 2 (rarely 3) pedicels, not long persistent, ovate-attenuate, puberulent with tapering hairs, 3.5–6.5 × 2–3.5 mm. Calyx green to purple, 5-lobed, puberulent and pilose on both lobes, 1.5–3 mm long. Standard pink or dark red with white apex, obovate, retuse at apex, glabrous, 2–3 × 1–3 mm. Wing petals green, oblong, slightly obtuse at apex, auriculate and short-clawed, 3–5 × 1.5–3 mm. Keel petals pale purple, scythe-shaped, long-clawed. Loment sessile to shortly stipitate, 2–5 articled; articles reticulate, rounded on the lower side and indented at the constrictions.

Phenology: Flowers from July to May; fruits from September to May.

Diagnostic characters: G. ramosissima is similar to G. barbata in terms of growth habit and inflorescence type, but can be distinguished by leaflet shape and inflorescence length. The leaflet shape in G. ramosissima is narrowly obovate to oblong-elliptic and the inflorescence length is 68–182 mm long, compared to orbicular-oval or lanceolate and 15–69 mm long in G. barbata. Stems are strigose with slender branches spreading and appressed hairs.

Distribution: G. ramosissima is widely distributed across Nigeria, covering all six geopolitical zones.

Additional specimens examined: NORTH-EAST NIGERIA. Adamawa State: Along River Serti, 13 February 1979, Fagbemi 360 (FHI); Mayselbe-Serti Road, 22 November 1978, Odewo 836 (FHI); Dinga-Takum Road, 21 January 1980, Ekwuno 265 (FHI). NORTH-WEST NIGERIA: Kaduna State: Kontagora, Zaria, 6 April 1974, Faremi 362 (IFE). NORTH CENTRAL NIGERIA. Benue State: Holi Idoma Forest Reserve, 4 March 1959. Stanfield 164 (FHI). (F.C.T): Keffi Road, Abuja, 19 January 1970, Owoseye 33 (IFE); Mandala Forest Reserve, Abuja, 16 June 1970, Owoseye 161 (IFE); Abuja, 16 June 1970, Owoseye 34 (IFE); Abuja, 21 May 1968, Lowe 1320 (UIH). Kogi State: Ajaka Village, 11 April 2001, Daramola 156 (IFE). Kwara State: Elekoyangan, Ilorin, Bacita road, 23 November 1971, Daramola 706 (FHI); Streamside near Lampese, 7 September 1978, Daramola 349 (FHI). Plateau State: Serti and Gashaka area, Sarduana, 24 March 1970, Hall s.n (IFE); Near Njawi, North of town, Mambila, 24 August 1973, Medlar 920 (IFE). SOUTH-WEST NIGERIA. Ekiti State: Ibilo-Ikare roadside, 18 April 1970, Lowe 2093 (UIH); North East of Ado-Ekiti, 6 January 1970, Lowe 1992 (UIH); Ikole Ado-Ekiti, 18 April 1970, Lowe 2100 (UIH). Lagos State: Epe, 31 July 1972, Ogunyemi sn (IFE); Univ. of Lagos Botanical Garden, 29 May 1973, Daramola 212 (FHI); Epe, 31 July 1972, Ogunyemi sn (IFE). Ogun State: Ohumber Forest Reserve, 22 June 1981, Ariwoade 202 (FHI); Olokomeji Forest Reserve, 3 November 1959, Hopkins 54 (FHI); Shaka, 29 January 1974, Ekwuno 141 (FHI); Ohumbe Forest Reserve, 23 June 1981, Arowolo 219 (FHI); Omo Forest Reserve, 21 July 1977, Daramola 383 (FHI). Ondo State: Between Ikun and Idoani, 25 June 1979, Daramola 10 (FHI); Okitipupa Forest Reserve, 11 September 1982, Ibhanesebhor 52 (FHI); Ido-Ifaki Road, 24 April 1973, Olorunfemi 246 (FHI); Irele Odeomi Ajagba Road, 4 July 1980, Olorunfemi 158 (FHI); Erin-odo, 18 December 1973, Akabogu 35 (IFE); Erin-odo, 18 December 1973, Akabogu 35 (IFE). Osun State: Univ. of Ife campus, 10 July 1969, Lufadeju 29 (IFE); Univ. of Ife campus, 4 July 2003, Daramola sn (IFE). Oyo State: Fashola Agric., 10 August 1980, Daramola 234 (FHI); Along Iwo-Ibadan Road, 19 November 1985, Odewo 55 (FHI); Ogba River Okeho Road, 7 November 1968, Olorunfemi 309 (FHI); Bodija, Ibadan, February 1966, Guile 792 (IFE); Ogba river, Okeho road, 15 October 1968, Olorunfemi 455 (IFE); IITA, Ibadan, 29 September 2000, Daramola sn (IFE); School of Forestry Jericho roadside, 31 October 1994, Ibhanesebhor 599 (FHI); Road side IITA, 30 March 1980, Inah 87 (UIH); Idi-Ose Ibadan, 30 March 1980, Inah 88 (UIH); Ogba river okeho road, 15 October 1968, Olorunfemi 422 (UIH). SOUTH-EAST NIGERIA. Abia State: Farmland, 27 March 1974, Daramola 256 (FHI); Umuahia, 27 March 1972, Lowe 2465 (UIH); Methodist College roadside, 24 October 1972, Daramola 245 (FHI). Anambra State: Eme River, 21 January 1980, Ekwuno 144 (FHI). Imo State: Onaji Forest Reserve, 1 February 1981, Ekwuno 355 (FHI); Bende Forest Reserve, 12 November 1981, Ekwuno 478 (FHI). SOUTH-SOUTH NIGERIA: Cross-River State: Awi Forest Reserve, 8 April 1975, Latilo 08 (FHI); Okorshie, 22 February 1982, Ekwuno 949 (FHI); Oban Group Forest Reserve, 12 May 1978, Emwiogbon 373 (FHI); Federal Housing Estate, 12 January 1976, Daramola 52 (FHI); Ikom Forest Reserve, 20 September 1978, Ariwaodo 864 (FHI); Old farm Itekpa village, 12 February 1980, Inah 69 (UIH); Awi Forest Reserve, 4 June 1982, Ekwuno 559 (FHI); Iyanmtta Forest Reserve, 18 January 1982, Ekwuno 644 (FHI); Ikom Forest Reserve, 11 December 1981, Ekwuno 794 (FHI). Delta State: Utorogu flows, 6 March 2003, Daramola sn (IFE); Utoragu gas, 20 March 2003, Daramola 45 (IFE); Warri-Porthacourt road, Asaba, 4 January 2002, Daramola sn (IFE). Edo State: Igara, Auchi, 31 October 1969, Lowe 11785 (IFE); Iruma Forest Reserve, 17 January 1977, Gbile 84 (FHI); Igarra Auchi, 21 Oct 1969, Lowe 1874 (UIH); North West of Auchi, 17 March 1964, Lowe 376 (UIH). Rivers State: Elewenle flare, Porthacourt, 21 June 1973, Isichei 1057 (IFE); Porthacourt-Aba Road, 16 Sept 197, without name (FHI); Kaima Kolokuma area, 19 December 1973, Lowe 432 (UIH).

G. setigera (E.Mey) H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(2): 116. 2018. Nicolsonia setigera E. Mey., in Comm. Pl. Afr. Ausr.: 124. 1836. Desmodium setigerum (E. Mey.) Benth. Ex Harv., in W.H. Harvey & auct. Suc. (eds.), Fl. Cap. (Harvey) 2: 229. 1862. Type: South Africa, Transkei. Umzimvubu River, without date, Drege 446 [Holotype: B; Isotypes: W, K, fide Schrire [24].

Perennial herb, more or less creeping, prostrate, or scrambling, spreading across the ground. Stems patently hirsute or setose, much-branched, with spreading silky hairs. Leaves trifoliolate; stipules obliquely ovate-attenuate, 3–8 mm. long, ± puberulent on the outer surface; petiole densely long-pilose, 4–42 mm long; leaflets obovate to oblanceolate, 5–35 × 4–25 mm, apex and base rounded; appressedly pilose on both surfaces. Inflorescences axillary and terminal racemes, long and lax, remotely flowered, 5–53 mm long. Flowers pale purple, pink, or cream-tinged blue; pedicels filiform, elongate, 5–15 mm long; primary bracts ovate-lanceolate, hairy, subtending two pedicels, 3–7 × 1.5–3 mm; secondary bracts usually absent. Calyx narrowly triangular, puberulent and pilose on both lobes, 5-fid with spreading bristle hairs. Standard mauve, obovate, retuse. Wing petals violet; Keel petals white. Loment sessile to shortly stipitate, green, flat, hairy, indented on one side, 5–19 × 1–4 mm up to 6 articles; articles separating but not dehiscing.

Phenology: Flowers from July to September.

Diagnostic characters: G. setigera is similar to G. adscendens in leaflet indumentum, but the upper surface of the leaflets is densely pilose in G. setigera compared to G. adscendens, which is glabrous on the upper surface.

Distribution: Grona setigera occurs in Bauchi, Gombe, and Gembu in North-East Nigeria; Umuahia, Nsukka, and Eha-Amufu in South-East Nigeria; and Port Harcourt and Obudu in South-South Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA. Bauchi State: East of Aliya village, 10 January 1972, Latilo 315 (FHI). Gombe State: Edge of Rice farm, 30 December 1971, Latilo 142 (FHI). Taraba State: Kamatan Forest Reserve, 24 January 1969, Daramola 455 (FHI); Mayo-Ndaga, 9 January 1976, Ekwuno 258 (FHI). SOUTH-EAST NIGERIA. Abia State: Agric research station, 29 January 1965, Latilo 962 (FHI). Enugu State: Univ. Of Nigeria, Nsukka, 2 November 1973, Daramola 208 (FHI); Eha-Amufu, 22 December 1992, Ariwaola 342 (IFE). SOUTH-SOUTH NIGERIA: Cross-River State: Obudu cattle ranch, 13 April 1973, Medler 794 (IFE). Rivers State: Port Harcourt-Aba Road, 18 September 1975, Latilo 245 (FHI).

G. triflora (L.) H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(2): 117. 2018. Hedysarum triflorum L., in Sp. Pl. [Linnaeus] 2: 749. 1753. Aeschynomene triflora (L.) Poir., in Encycl. [J. Lamarck & al.] 4(2): 451. 1798. Pleurolobus triflorus (L.) J.St.-Hill, in Nouv. Bull. Sci. Soc. Philom. Paris 3: 192. 1812. Desmodium triflorum (L.) DC., in Prodr. 2: 334. 1825; Benth., in Miq., Pl. Jungh.: 221. 1852; Bak., in Fl. Trop. Afr. 2: 166. 1871; Schub., in Fl. Congo Belge et Ruanda-Urundi. 5: 187 1954; Hepper in Fl. W. Trop. Afr., ed. 2 [Hutchinson & Dalziel] 1: 584. 1958. Sagotia triflora (L.) Duchass. & Walp., in Linnaea 23: 738. 1851; Nicolsonia triflora (L.) Griseb., in Abh. Königl. Ges. Wiss. Göttingen 7: 202. 1857; Meibomia triflora (L.) Kuntze, in Revis. Gen. Pl. 1: 197. 1891. Type: India, without date, Herb. Hermann 1:21, no 297b [lectotype: BM Barcode BM000594452 [Web!], designated by Pedley in Turland & Jarvis [25].

Annual or perennial herb, creeping, stoloniferous, and prostrate, spreading across the ground, 1–4 m long. Stems terete and striate to angular, branched, grey or light brown, moderately to densely covered with long white pilose hairs; branches rooting at nodes. Leaves trifoliolate; stipules persistent, brown, striate, obliquely ovate, 2.5–6 × 1–2.5 mm wide, pilose on abaxial surface; petiole 3–8 mm long, puberulent and long pilose; leaflets obovate, 3–13 × 2–10 mm, apex rounded or emarginate, base rounded; essentially glabrous and reticulate above, usually abundantly pilose beneath or only so on midrib and margins. Inflorescences axillary racemes, 11–55 mm long, composed of 3–4 pairs of flowers; peduncle red. Flowers purple, pink, blue (inside) and white (beneath); pedicels 4.5–8 mm long, puberulent to pilose; primary bracts ovate-attenuate, long-persistent, subtending two pedicels, 2–3 × 5–10 mm; secondary bracts rarely present. Calyx bilabiate, green, 5-lobed, with reddish midrib, ciliate and white pilose, 1–3.5 mm long. Standard orbicular and clawed, 3–4 × 1.5–3.5 mm. Wing petals oblong, long-clawed, 2.5–4 × 0.5–1 mm. Keel petals scythe-shaped, long-clawed. Loment sessile, green, sticky, hairy, 3–5 articled, indented on one side only, 2–11 × 1–3.5 mm, glabrous to pubescent; articles quadrate, indehiscent.

Phenology: Flowers from June to October.

Diagnostic characters: G. triflora can be characterized by its small inconspicuous leaflets, 3–13 × 2–10 mm, and inflorescence type, which is an axillary raceme and composed of 3–4 pairs of flowers.

Distribution: G. triflora is distributed in all six geopolitical zones in Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA. Adamawa State: Dongo-Takum Road, 21 January 1980, Ekwuno 266 (FHI). NORTH-WEST NIGERIA: Kaduna State: Institute of Agric Research ABU, 5 December 1968, Olorunfemi 242 (FHI). NORTH CENTRAL NIGERIA. Federal Capital Territory: Keffi town along Abuja road, 31 May 1976, Olorunfemi 142 (UIH). (Kogi): Field at the school compound, 26 March 2001, Daramola 96 (IFE). Kwara State: Ogori-Okenne Road, 23 November 1978, Olorunfemi 36 (FHI); Ankpa-Ogodo Road, 4 September 1973, Gbile 145 (FHI). SOUTH-WEST NIGERIA. Lagos State: Igbosere area, 10 August 1952, Lowe 24 (UIH); Festac village, 14 July 1981, Fagbemi 80 (FHI). Ogun State: Shaka Forest Reserve, 29 January 1974, Ekwuno 208 (FHI). Osun State: Univ. of Ife campus, 16 August 1973, Akabogu 122 (IFE); Univ. of Ife campus, 6 October 1971, Sijuade 364 (IFE); Univ. of Ife campus, 24 June 19S69, Ogunremi 12 (IFE). Oyo State: Bush near Forestry School, 8 December 1976, Olorunfemi 175 (FHI); Ofiki Area, 10 August 1980, Daramola 145 (FHI); University of Ibadan campus, 5 November 1964, Lowe 458 (UIH); Bodija Ibadan, 4 May 1970, Lowe 845 (UIH); University of Ibadan campus, 4 April 1980, Inah 89 (UIH); University of Ibadan campus, 17 November 1979, Inah 54 (UIH); University of Ibadan campus, 1 April 1980, Inah 90 (UIH); Igbetti, 3 November 1974, Faremi 544 (IFE); Federal Agric. MP Ibadan, 18 December 1969, Adewole 44 (IFE); Ibadan, April 1966, Guile 810 (IFE). SOUTH-EAST NIGERIA. Enugu State: Enugu Forest Reserve, 6 November 1957, Keay 246 (FHI); Akpaka footpath, 19 February 1959, Onochie 82 (FHI); Ngwo Forest, 26 January 1973, Daramola 192 (FHI). Imo State: Oguta Lake, 19 January 1982, Ekwuno 176 (FHI). Anambra State: Ngwo, 7 April 1978, Ariwaodo 214 (FHI). SOUTH-SOUTH NIGERIA: Cross-River State: Ikom Forest Reserve, 4 January 1982, Ekwuno 753 (FHI).

3.3. Desmodium Desv.

Desmodium Desv., J. Bot. Agric. Hortic. 1(2): 122, t. 5. 1813—nom. cons. Type species: Desmodium scorpiurus (Sw.) Desv.

Desmodium sect. Desmodium DC., Prodr. 2: 325. 1825. Type species: Desmodium scorpiurus (Sw.) Desv.

Desmodium subgen. Desmodium DC., Prodr. 2: 325. 1825, emend. Ohashi, Ginkgoana 1: 120. 1973.

Shrubs or herbs, rarely small trees. Leaves alternate, petiolate, stipulate; leaflets petiolulate and stipellate; stipules free or connate, persistent or caducous. Inflorescences axillary and terminal, racemose to racemose paniculate; primary bracts striate and ciliate, each subtending 1 flower, or a fascicle of 2 to several flowers; secondary bracts often present, similar to the primary bracts, each subtending a single flower; bracteoles absent; flowers pedicellate. Calyx 5-lobed, often bilabiate; upper lip 2-lobed, nearly entire or shallowly bifid, lower lip 3-toothed with the central tooth longer than the laterals. Standard generally obovate, deeply or slightly retuse at apex, slightly clawed. Wing petals obtusely oblong, truncate above, auriculate and short-clawed. Keel petals mostly oblong, scythe-shaped, partially fused above, long-clawed. Loments usually stipitate, indehiscent, or tardily dehiscent; articles linear to orbicular, the surfaces glabrous to densely pubescent with straight tapering or hooked trichomes, or these only on sutures. Stamens 10, diadelphous.

Species in Nigeria:

D. scorpiurus (Sw.) Poir.

D. tortuosum (Sw.) DC.

D. intortum (Mill.) Urb.,

D. ospriostreblum Chiov. (insufficiently known)

D. distortum J.F.Macbr. (insufficiently known)

D. procumbens (Mill.) Hitchc. (insufficiently known)

D. uncinatum (Jacq.) DC. (insufficiently known).

Key to the species

• 1a. Plant erect or ascending; fruits twisted; articles elliptical-rhomboidal………………………………………………………………………………………………………..D. tortuosum
• 1b. Plant climbing or creeping; fruits not twisted; articles narrowly elliptic or oblong-elliptic………………………………………………………………………………………………2
• 2a. Stipules ovate-acuminate; articles oblong-elliptic, basal suture much more indented than the upper suture; inflorescence length 24–30 mm………………………D. intortum
• 2b. Stipules obliquely ovate; articles narrowly elliptic, both sutures equally indented and notched between the articles; inflorescence length 38–115 mm…………D. scorpiurus

D. intortum (Mill.) Urb. in Symb. Antill. 8:292. 1920, non Fawc. & Rendle, in Fl. Jam. 4: 34 1920). Hedysarum intortum Mill., in Gard. Dict., ed. 8: 11. 1768. Meibomia intorta (Mill.) S.F.Blake, in Bot. Gaz. 78: 286. 1924. Type: Jamaica, 1731, Houston s.n. (Syntypes: BM barcode BM000931657 [web!], E barcode E00346848 [web!]).

Spreading, prostrate, leguminous herb or subshrub with a strong taproot, lightly appressed pubescent, with more constricted branches. Stems reddish-brown up to 60–90 cm tall, glabrescent with hooked or recurved hairs, glandular, non-twining. Leaves trifoliolate; stipules ovate-acuminate, 1–3.5 × 1–3 mm, carducous; leaflets ovate or elliptic, covered with ascending hairs on both surfaces, 15–57 × 12–30 mm; apex acute with pointed hairs; base rounded to truncate; margin entire; petiole pubescent, 15–61 mm long. Inflorescences terminal and axillary raceme, less branched, 24–30 mm long. Flowers pale purple, deep lilac to deep pink in colour; pedicels uncinated, puberulent, 4–6 mm long; bracts ovate-acuminate, finely striate, puberulent on abaxial surface, 1.5–4 × 0.5–1 mm. Calyx bilabiate, teeth of the lower lobe longest. Standard pink, purplish, red to violet or greenish white. Wing petals oblong. Loments oblong-elliptic, basal suture much more indented than the upper suture, 12–44 × 1–3 mm, 7–11 articled; article covered with brownish hooked hairs, breaking up at maturity.

Phenology: Flowering and fruiting from July to November.

Diagnostic characters: D. intortum can be distinguished from other species by their articles (basal suture much more indented than the upper suture compared to D. scorpiurus and D. tortuosum, in which both sutures are equally indented) and its small inflorescence length (24–30 mm vs. 38–115 mm in D. scorpiurus and 65–112 mm in D. tortuosum). It is similar to D. scorpiurus in growth but can be distinguished by its stipule shape, which is ovate-acuminate compared to obliquely ovate in D. scorpiurus.

Distribution: Desmodium intortum is found only in Sardauna and Jalingo in North-East Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA. Taraba State: North-East of Sardauna, 22 August 1985, Soladoye 142 (FHI).

D. scorpiurus (Sw.) Poir., in G.-F. Cuvier, Dict. Sci. Nat., ed. 2. 13: 110. 1819. Hedysarum scorpiurus Sw., in Prodr. Veg. Ind. Occ.: 107. 1788. Meibomia scorpiurus (Sw.) Kuntze, in Revis. Gen. Pl. 1: 198. 1891. Type: Jamaica, Swartz s.n. [lectotype S barcode S-R-2774 [web!], designated by Schubert [21]; isolectotypes: B barcode BW13825010 [web!], LD barcode LD1263645 [web!], S barcode S13-17668 [web!], designated by Nawale and Bhuktar [26].

Perennial, prostrate, creeping, straggling climber, trailing and procumbent herbaceous woody plant. Stems fine, weak, green, solid, puberulent, twisted, and rooting at nodes. Leaves trifoliolate; stipules persistent, obliquely ovate, 1–4 × 0.5–2 mm, puberulent; leaflets elliptic or ovate, puberulent interspersed with appressed pilose hairs on both surfaces, 8–48 × 5–32 mm, apex obtuse; margins entire with reticulate venation; petiole striate, sulcate, puberulent intermixed with pilose hairs, 12–39 mm long. Inflorescences terminal and axillary racemes to racemose-paniculate, 38–115 mm long. Flowers white, pale purple, or red; pedicels puberulent to pilose, 4–8 mm; bracts ovate-acuminate, striate, puberulent on both surfaces, each subtending an indeterminate number of pedicels, 2–3 × 1–1.5 mm. Calyx bilabiate, teeth of both lobes somewhat ciliate; central tooth of lower lobe long attenuate. Standard broadly obovate, retuse at apex and narrowed at base. Wing petals oblong, truncate at apex, auriculate and short-clawed. Keel petals narrowly obovate, long-clawed. Loments shortly stipitate, narrowly elliptic, bead-like, deeply indented on both sides, 18–44 × 2.5–4 mm, 4–8 articled; articles indehiscent, surfaces strongly and closely reticulate-hairy.

Phenology: The species flowers from July to October.

Diagnostic characters: D. scorpiurus and D. intortum are similar in habit, but their articles differ. D. scorpiurus is narrowly elliptic (Figure 2A) in bead form and indented on both sides between the articles, compared to D. intortum, which is oblong-elliptic (Figure 2C), and the basal suture is much more indented than the upper suture. It can also be distinguished from D. tortuosum by its fruit shape (narrowly elliptic vs. elliptical-rhomboidal (Figure 2B) and growth habit, which is creeping or climbing vs. ascending or erect in D. tortuosum.

Distribution: Desmodium scorpiurus is found in Agaie, Duma, and Ilorin in North Central Nigeria; Ibadan, Ile-Ife, Abeokuta in South-West Nigeria; Zaria in North-West Nigeria; and Bendel, Obudu, Calabar in South-South Nigeria.

Additional specimens examined: NORTH-WEST NIGERIA: Kaduna State: Ahmadu Bello Univ. Plantation, 13 December 1979, Fagbemi 142 (FHI); Dan Fodio Hall Ahmadu Bello Univ., 27 August 1976, Olorunfemi 106 (FHI); Zaria-Kano road, 14 July 1975, Gbile 90 (FHI); Institute of Agric and Forest office field, 24 October 1969, Daramola 455 (FHI). NORTH CENTRAL NIGERIA: Kwara State: Bacita Sugar Industry, 13 December 1971, Olorunfemi 524 (FHI); Ilorin-Mokwa, 9 May 1971, Lowe 73 (UIH); Ilorin-Mokwa, 22 September 1971, Lowe 74 (UIH). Niger State: Agaie-Baro Road, 4 May 1977, Olorunfemi 120 (FHI). SOUTH-WEST NIGERIA. Ogun State: Olokomeji Abeokuta, 3 December 1963, Lowe 173 (UIH). Osun State: Univ. of Ife campus, 7 October 1976, Faremi 1068 (IFE); Univ. of Ife campus, 14 January 1966, Stanfield 456 (FHI); Univ. of Ife campus, 15 October 1976, Faremi 1091 (IFE). Oyo State: Catering rest house, 5 September 1964, Latilo 145 (FHI); Eruwa, 9 November 2017, Chukwuma 452 (FHI); Forestry hill edge of farmland, 30 October 1962, Stanfield 454 (FHI); Forestry Research Headquarters, 21 October 1961, Stanfield 224 (FHI); Eruwa, 22 January 2013, Chukwuma 456 (FHI); Quarter garden Ibadan, 8 October 1961, Stanfield 477 (FHI); Moor Plantation, 30 October 1968, Ogunyemi 15 (IFE); Ibadan, Oct 196, Guile 798 (IFE); Fed. Agric. Moor Plantation, 23 December 1969, Adewole 15 (IFE); Fed Agric Research M.P, 25 November 1969, Adewole 51 (IFE); roadside Ibadan, 2 January 1965, Lowe 576 (UIH); Jericho reservation, 10 April 1966, Lowe 960 (UIH); Near stream bank Ibadan, 20 December 1979, Inah 57 (UIH); University of Ibadan campus, 18 November 1976, Lowe 2919 (UIH). SOUTH-SOUTH NIGERIA: Cross-River State: Ipong Forest Reserve, 14 September 1979, Ariwaodo 103 (FHI); Abuochiche, Ogoja, 12 February 1980, Inah 68 (UIH). Edo State: Osogho plain, 17 December 1986, Ariwaodo 28 (FHI); Owan Forest Reserve, 25 October 1977, Olorunfemi 20 (FHI).

D. tortuosum (Sw.) DC., in Prodr. 2: 332 1825). Knaap-van Meeuwen, Reinwardtia 6(3): 260. 1962; Verdcourt, Man. New Guinea Legumes 408, fig. 94f. 1979; Ohashi, J. Jap. Bot. 79: 138. 2004. Hedysarum tortuosum Sw., in Prodr. Veg. Ind. Occ.: 107. 1788. Meibomia turtuosa (Sw.) Kuntze, in Revis. Gen. Pl. 1: 198. 1891. Type: Jamaica, without date, Swartz s.n. (lectotype: S barcode S10-14459 [web!] designated by Schubert [22].

Annual, erect slender woody herb with hooked clinging hairs, about 180 mm high or subshrub to 460 mm high, with pubescent branches. Stem brown or pale green, solid, purple at the nodes, pubescent and pilose. Leaves trifoliate; stipules long persistent, obliquely ovate-attenuate, ciliate; leaflets 25–75 × 10–35 mm, ovate-lanceolate in shape, obtuse at apex, cuneate at base, entire at margin, pale green with prominent nerves beneath, puberulent to pilose on both surfaces, ciliate; petiole brown, pubescent, 10–43 mm long. Inflorescences terminal and axillary raceme or paniculate, 65–112 mm long. Flowers pink, yellow or purple; pedicel pubescent, 11–14 mm long; bracts deciduous, setaceous, ovate-attenuate, subtending 2 or more pedicels, minutely puberulent on abaxial surface, 2–5 × 1–2.5 mm. Calyx bilabiate, teeth of both lobes ciliate. Standard obovate, retuse at apex and narrowed to base. Wing petals oblong without callosities, auricled and short-clawed. Keel petals obliquely oblong, broader above, with callosities. Loments small, twisted, deeply indented on both sides, 3–7-articled; articles elliptical-rhomboidal, 3–5 × 2–4 mm, hooked hairy.

Phenology: Flowering from February to April and fruiting from March to June.

Diagnostic characters: Desmodium tortuosum can be characterized by its growth habit and twisted lomentaceous fruit. It is a self-supporting erect or ascending subshrub compared to D. scorpiurus and D. intortum, which are climbing or creeping plants. The articles of D. tortuosum are elliptical rhomboidal or nearly isodiametric, as long as wide. It can also be distinguished from other species by its pedicel length (11–14 mm vs. 4–8 mm in D. scorpiurus and 4–6 mm in D. intortum).

Distribution: Desmodium tortuosum is found in all six geopolitical zones in Nigeria, with the exception of the South-East.

Additional specimens examined: NORTH-EAST NIGERIA: Adamawa State: Agric Oil Pam Avenue Serti, 22 August 1978, Daramola 37 (FHI); Along farmland Serti, 27 February 1979, Fagbemi 322 (FHI). Bauchi State: North of Yolde, 17 January 1968, Latilo 198 (FHI). Taraba State: Beli Forest Reserve, 27 July 1972, Daramola 187 (FHI). NORTH CENTRAL NIGERIA. Kwara State: Ankpa-Angwa Ogebe bush, 3 December 1974, Olorunfemi 142 (FHI); Wildlife School Site Natural Reserve, 24 October 1979, Gbile 351 (FHI). SOUTH-WEST NIGERIA: Osun State: Awo-ede, 21 November 2013, Omomoh 367 (IFE). Oyo State: Forest Research Headquarters, 3 March 1965, Standfield 424 (FHI); Moor plantation IAR&T, 4 March 1959, Stanfield 243 (FHI); Ore-Meji Opposite Boys chemist Mokola Ibadan, 3 June 1969, Gbile 213 (FHI); Eleyele Waterworks Ibadan, 29 October 1984, Lowe 457 (FHI); Forestry Research Institute of Nigeria Compound, 5 July 2011, Osiyemi 224 (FHI); Polytechnic Ibadan campus, 5 May 1977, George 204 (FHI); Old Army barracks compound, 16 March 1963, Onyeachusim 344 (FHI); Bodija, Ibadan, March 1966, Guile 806 (IFE); Bodija, Ibadan, March 1966, Guile 807 (IFE); Ore-meji, Mokola, Ibadan, 15 May 1969, Binuyo 213 (IFE); Eleyele Waterworks, February 1967, Guile 805 (IFE); Govt. Colleg. Apata Ganga, 13 December 1970, Adewole 73 (IFE); Off Ojo village, Ibadan, 25 November 1968, Ogunyemi 67 (IFE); University of Ibadan campus, 18 November 1976, Lowe 2918 (UIH); University of Ibadan campus, 23 December 1967, Hill 780 (UIH); Oremeji opposite Boye chemist Mokola, 3 June 1969, Gbile 213 (UIH); Eleyeile Waterworks, 27 October 1984, Lowe 4570 (UIH); IITA North of Ibadan, 7 July 1985, Lowe sn (UIH); Ibadan, 1 November 1980, Savory 165 (UIH). SOUTH-SOUTH NIGERIA. Cross-River State: Ogoja-Obudu road, 9 February 1980, Inah 66 (UIH); Old farmland opposite Bekwara school, 13 February 1980, Inah 71 (UIH); Obubru-Ikom road, 21 February 1980, Inah 80 (UIH).

3.4. Pleurolobus J.St.-Hil.

Pleurolobus J.St.-Hil., in Nouv. Bull. Sci. Soc. Philom. Paris 3: 192. 1812 & J. Bot. Agric. 1(2): 61. 1813; H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(3): 184. 2018. Type species: Pleurolobus gangeticus (L.) J. St.-Hil.

Desmodium sect. Heteroloma Benth. [unranked] Latifolia Benth., in Miq., Pl. Jungh. 224 1852), in adnot., p.p., incl. ‘3. D. gangeticum DC.’, cet excl.; H.Ohashi, in Ginkgoana 1: 178 1973, ut ‘ser. Latifolia.’ Type species: P. gangeticus (L.) J.St.-Hill. ex H.Ohashi & K.Ohashi.

Subshrubs or shrubs to large shrubby forms up to 200 cm tall. Leaves alternate, unifoliolate or trifoliolate, stipulate, petiolate; stipules persistent or caducous; leaflets chartaceous, entire, principal lateral nerves directly reaching the margin, reticulate veins inconspicuous. Inflorescences terminal and axillary pseudoracemes or racemose-paniculate to 300 mm long; primary and secondary bracts present, bracteoles absent. Flowers 2 to 4 per node, pedicellate. Calyx broadly campanulate, 4-lobed. Standard obovate to orbicular, rounded or emarginate. Wings shorter than keel petals, both short-clawed. Loment linear, 12–43 mm long, (4–)6–8 articles, abaxial suture slightly to deeply indented; articles broadly oblong with dense minute hooked hairs.

Key to the species

• 1a. Leaves simple or unifoliolate; inflorescence axillary and terminal pseudo-raceme ………………………………………………………………………………………...P. gangeticus
• 1b. Leaves pinnately compound or trifoliolate; inflorescence racemose-paniculate……………………………………………………………………………………………P. salicifolius

P. gangeticus (L.) J.St.-Hill. ex H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(3): 184. 2018. Hedysarum gangeticum L., in Sp. Pl.: 746. 1753. Aeschynomene gangetica (L.) Poir, in J. Lamarck et al., Encyc. Meth. Bot. 4(2): 453. 1798. Desmodium gangeticum (L.) DC., Prodr. 2: 327. 1825; Benth., in Miq., Pl. Jungh. 228 1852); B. G. Schub., in Fl. Trop. E. Afr. Legum. 3, Papil. 1: 467. 1971; H.Ohashi, Ginkgoana 1: 184. 1973; Ali, Fl. W. Pakistan 100, Pap. 348. 1977; Verdc., Man. New Guinea Leg. 397. 1979; T. C. Huang & Ohashi, Fl. Taiwan ed. 2, 3: 253, pl. 121. 1993; H.Ohashi, in J. Jap. Bot. 70: 113. 1995; Pedley, in Rev. Handb. Fl. Ceylon 10: 182, 1996 & in Austrobaileya 5: 249. 1999; H.Ohashi, in J. Jap. Bot. 79: 122. 2004; P. H. Huang & H.Ohashi, in Fl. China 10: 272. 2010. Meibomia gangetica (L.) Kuntze, in Revis. Gen. Pl. 1: 196. 1891. Type: “Habitat in India” without date, Herb. Linn. 921.13 (lectotype: LINN No 921.13 [Web!], designated by Fawcett & Rendle [27].

Perennial, small erect woody herb or undershrub up to 1.5 m high. Stems prostrate to erect, scabrid, angular, uncinulate-puberulent and abundantly strigose with upwardly directed tapering hairs. Leaves simple or unifoliolate; stipules persistent or caducous, narrowly triangular to linear, 3–7 × 1.5–2.5 mm, puberulent on the outer surface, ciliate; petiole puberulent, 7–32 mm long; leaflets 25–166 × 17–63 mm, elliptic-acuminate or ovate, coriaceous, puberulous with very short hairs above, almost glabrous, pilose with much longer hairs beneath; apex acute; base rounded; margin entire. Inflorescences slender, lax-flowered, terminal and axillary pseudoracemes or paniculate, 43–220 mm long; primary bracts each subtending 3 or more flowers, linear or lanceolate, pilose; secondary bracts each subtending one pedicel, linear to subulate, ciliate, all persistent; flowers small, pinkish, white, or pale purple; pedicel puberulent, 3–8 mm. Calyx pale green tinged reddish, obtuse at base, inside glabrous, outside hairy, puberulent and strigose, teeth of both lobes ciliate, 2–3.5 mm long, lateral teeth slightly shorter, 2–2.5 mm long. Standard whitish-blue, obovate or oblanceolate, emarginated at apex, attenuate at base and short-clawed, 2.5–4.5 mm long. Wing petals purple, broadly oblong, obtuse at apex and short-clawed, 1.8–3.5 × 5–1.5 mm. Keel petals red, obtuse apex, and short-clawed. Loments sessile to shortly stipitate, deeply indented on one side with sticky hairs, puberulent on surfaces, 12–21 × 1.5–3 mm, 6–8 articled; articles uncinulate-puberulent on surfaces with some stiff tapering hairs scattered on sutures (Figure 3).

Phenology: Flowering and fruiting occur twice in a year, from May to June and from September to October.

Diagnostic characters: P. gangeticus and P. salicifolius are similar in growth habit but can be distinguished by their leaf type and stipule shape. P. gangeticus has unifoliolate leaves compared to trifoliolate leaves in P. salicifolius, with a stipule shape that is narrowly triangular to linear vs. ovate-lanceolate in P. salicifolius. It can also be distinguished by its inflorescence, which is axillary and terminal pseudoraceme, compared to racemose-paniculate in P. salicifolius.

Distribution: P. gangeticus is widely distributed in all six geopolitical zones in Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA: Adamawa State: Gombi Road, 5 March 1982, Odewo 101 (FHI). Bauchi State: Mubi Forest Reserve, 13 September 1972, Daramola 1281 (FHI); Mubi forest reserve, 3 May 1972, Daramola 1281 (UIH). NORTH-WEST NIGERIA: Kaduna State: Zaria-Kano road, 23 October 1977, Soladoye 223 (FHI); Zaria River, 7 July 1975, Gbile 67 (FHI). NORTH CENTRAL NIGERIA. Federal Capital Territory: Abuja, 2 January 1971, Owoseye 155 (IFE); Mayanke falls, Abuja, 1 October 1970, Sijuade 166 (IFE); Savanna forest, Abuja, 17 June 1970, Owoseye 29 (IFE); Abuja 21 May 1968, Lowe 1318 (UIH). Kwara State: Wildlife School Site Natural Reserve, 12 June 1980, Daramola 42 (FHI); Kaaba-Ogidi road, 27 November 1976, Olorunfemi 226 (FHI); Ilorin-Kishi, 1 November 1970, Lowe 88 (UIH); Ogamnana-Lokoja road, 20 September 1978, Olorunfemi 126 (FHI). Niger State: Gurara waterfall, 10 May 1977, Olorunfemi 130 (FHI); Dutsuna Udera Forest Reserve, 27 No 1969, Lowe 1425 (FHI); Sukurma Forest Reserve, 16 February 1977, Oguntayo 02 (FHI); Charati Railway Station, 12 October 1946, Keay 18 (FHI). SOUTH-WEST NIGERIA. Ekiti State: Ido-Ekiti near Paropa Grammar School, 11 November 1972, Latilo 1425 (FHI). Ogun State: Shala, 16 August 1974, Eimunjeze 24 (FHI); Orile-Ibara, 15 June 198, Ariwoade 41 (FHI); Olokomeju Forest Reserve, 4 March 1959, Stanfield 43 (FHI); Olokomeji Abeokuta, 27 October 1965, Ekekwe 12 (UIH). Osun State: Univ. of Ife campus, 27 March 1968, Latilo 527 (FHI); Ido-Osun, 15 April 1978, Gbile 526 (FHI); Univ. of Ife campus, 12 November 1970, Owoseye 30 (IFE); Univ. of Ife campus, 7 January 1968, Olutiola sn (IFE); Univ. of Ife campus, 10 October 1968, Ogunyemim 02 (IFE); Univ. of Ife campus, October 1966, Guile 787 (IFE); Univ. of Ife campus, 17 October 1973, Adelusi 10 (IFE); Ikire, Peletu Village, 8 November 1976, Gbile 425 (FHI); Univ. of Ife Agric. Farm, 14 July 1973, Akabogu 18 (IFE). Oyo State: Cocoa farmland, 22 June 1983, Odewo 150 (FHI); Idi-Ose road along Oyo road, 28 December 1979, Inah 59 (UIH); Ilero NTC flue cured, 23 March 1966, Latilo 455 (UIH); Shaki-Aguare road, 20 April 1950, Keay 195 (UIH); Agodi road, 13 April 1971, Lowe 79 (UIH); Igbetti, 22 October 1968, Olorunfemi 355 (IFE); Fed Agric. Quarters, Ibadan, 15 Dec 1969, Adewole 77 (IFE); University of Ibadan temporary site, 10 July 1975, Lowe 23 (UIH); University of Ibadan campus, 23 October 1950, Lowe 23 (UIH); Ibadan Niger College, 18 June 1970, Lowe 2497 (UIH); Ago-Are Okaka road, 1 December 1982, Olorunfemi 132 (FHI). SOUTH-EAST NIGERIA. Enugu State: Ebasua Nike, 1 July 1974, Olorunfemi 350 (FHI); Ogbaho Forest Reserve, 4 March 1959, Stanfield 192 (FHI). SOUTH-SOUTH NIGERIA: Cross-River State: Calabar-Ikoun road, Ekparabon Village, 10 October 1975, Latilo 2089 (FHI). New farm site, Bekwara, 13 February 1980, Inah 70 (UIH); Ogoja-Obudu road, 9 February 1980, Inah 65 (UIH); Ohoja-Ikom road, 19 February 1980, Inah 79 (UIH). Edo State: Uzairuwe Auchi, 20 October 1969, Lowe 54 (UIH); Uzairuwe, Auchi, 30 October 1969, Lowe 11763 (IFE).

P. salicifolius (Poir.) H.Ohashi & K.Ohashi, in J. Jap. Bot. 94(3): 145. 2019. Hedysarum salicifolium Poir., in Encycl. [J. Lamarck & al.] 6(2): 422 (1805), Encycl. 6: 422. 1805. Desmodium salicifolium (Poir.) DC., in Prodr. 2: 337. 1825; Schub., in Fl. Congo Belge et Ruanda-Urundi.5: 198, t. 15 1954; Hepper in Fl. W. Trop. Afr., ed. 2 [Hutchinson & Dalziel] 1: 584. 1958. Type: India, “Herb, de l’lnde de M. Poivre, without date, Poivre s.n. [(Holotype: P-JU 15552 [n.v.], fide Schrire [24]

Woody perennial straggling herb of about 1–3.6 m high. Stems brown with greenish-yellow bark, pilose with spreading or appressed hairs with short pubescence. Leaves long, trifoliolate; stipules brown, deciduous, ovate-lanceolate, 5–14 × 1–4 mm, puberulent on outer surface; petiole puberulent and pilose with grey indumentum, 12–50 mm long; leaflets 60–219 × 13–69 mm, lanceolate or ovate-elliptic in shape, acute or pointed at apex, rounded at base, entire to wavy at margin, glabrous on upper surface except for the midrib, softly pilose on the main venation or throughout on lower surface. Inflorescences terminal, racemose-paniculate, mostly dense, 37–149 mm long; primary bracts each subtending 2 pedicels; secondary bracts each subtending 1 pedicel; pedicels puberulous, 1–4 mm long, ovate- lanceolate; flowers slender, ranging in colour from purple, light blue or white, rather inconspicuous; pedicels puberulous, 1–4 mm long. Calyx yellow-green or brown, puberulous and pilose, lobes almost equal in length. Standard pink, almost orbicular, retuse at apex. Wing petals oblong, obtuse at apex, auricled and short-clawed. Keel petals pink or yellowish-green. Loments sessile to shortly stipitate, green, oblong, distinctly thickened at the margins, 2–7-articled, upper suture straight, the lower slightly indented; articles uncinulate-puberulent, interspersed with short fine pilosity on both surfaces and sutures, 4–7 × 2–3.5 mm.

Phenology: Flowering from May to July; fruiting from July to September.

Diagnostic characters: P. salicifolius is very similar to P. gangeticus in growth habit, but they can be distinguished by the leaf type, inflorescence type, and stipule shape. In P. salicifolius, the leaf type is trifoliolate with an inflorescence that is racemose-paniculate (Figure 4A) compared to the unifoliolate leaf with axillary and terminal pseudoracemes in P. gangeticus (Figure 4B). Stipules are ovate-lanceolate vs. narrowly triangular to linear in P. gangeticus.

Distribution: P. salicifolius is distributed in Ikirun, Oye-Ekiti, Shaki, Ibadan, and Ede in South-West Nigeria; Bauchi, Mambilla plateau, Gombe, and Song-Mubi in North-East Nigeria; Minna, Keffi, Ilorin, and New-Bussa in North Central Nigeria; and Zaria in North-West Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA. Adamawa State: Song-mubi motor road, 28 August 1968, Latilo 455 (FHI); Gashaka Forest Reserve, 24 March 1980, Ekwuno 65 (FHI); Gashaka Forest Reserve, 24 March 1980, Ekwuno 70 (FHI). Bauchi State: East of Aliya village, 4 December 1971, Latilo 64 (UIH). Gombe State: Sidi village, 30 December 1971, Latilo 145 (FHI). Taraba State: Nguroje-Kakara, 12 January 1976, Latilo 90 (FHI); Gembu Forest Reserve, 24 April 1980, Ekwuno 314 (FHI); Gallery Forest weedy palace, 5 January 1976, Daramola 274 (FHI); Mayo-Ndaga, 21 November 1975, Ibhanesebhor 193 (FHI); Maisamari-Nguroje road, 12 January 1976, Ekwuno 179 (FHI); Kakara Forest Reserve, 12 January 1976, Ekwuno 196 (FHI) NORTH-WEST NIGERIA. Kaduna State: Kurmi Bomo village, 2 January 1976, Olorunfemi 857 (FHI); North-West of Zaria, 30 June 1963, Stanfield 04 (FHI). Kano State: Zari-Kano road, 27 November 1972, Lowe 734 (UIH). NORTH CENTRAL NIGERIA. Kwara State: Wildlife school site Natural Reserve, 23 October 1979, Gbile 340 (FHI); Omuaran in a wet area, 20 March 1968, Daramola 455 (FHI). Niger State: Tegina Forest Reserve, 8 December 1970, Gbile 114 (FHI). Plateau State: Kefi Forest Reserve, 13 April 1984, Ariwaodo 21 (FHI). SOUTH-WEST NIGERIA. Ondo State: Ilefa road, 27 January 1982, Gbile 495 (FHI). 20474 (Oyo): Aroje-Shaki, 7 November 1968, Olorunfemi 308 (FHI). Osun State: Telemu village, Awo 28 November 1974, Faremi 1123 (IFE). Oyo State: Opposite Solomon hotel, 19 November 1981, Ariwaodo 189 (FHI); Ofiki-Shaki, 16 September 1980, Daramola 166 (FHI); Univ. of Ife damp site, 17 March 1977, Faremi 1302 (IFE); Bodija, Ibadan, October 1966, Guile 795 (IFE); Ojo road, Ibadan, 15 December 1969, Adewole 74 (IFE); Aroje, saki, 18 October 1968, Olorunfemi 455 (IFE); Bodija, Ibadan, October 1966, Guile 797 (IFE); Ojo village, Ibadan, 27 November 1968, Ogunyemi 05 (IFE); University of Ibadan botanical garden, 1 November 1950, Salvory 195 (UIH); Aroje-Shaki, 18 October 1968, Olorunfemi 455 (UIH).

3.5. Hylodesmum H.Ohashi & R.R.Mill

Hylodesmum H.Ohashi & R.R.Mill, in Edinb. J. Bot. 57(2): 173. 2000. Type species: H. podocarpum (DC.) H.Ohashi & R.R.Mill

Desmodium sect. Podocarpium Benth. in Miq., Pl. Jungh.: 226. 1852, pro parte, excl. D. axillare & D. securiforme. Type species: D. podocarpum DC.

Desmodium sect. Heteroloma Benth. subsect. Podocarpia (Benth.) Benth. & Hook.f., Gen. Pl. 1: 520. 1865.

Desmodium subgen. Podocarpium (Benth.) H.Ohashi, Ginkgoana 1: 120. 1973, pro parte, excl. sect. Monarthrocarpus (Merr.) H.Ohashi, pro parte, excl. D. dolabriforme Benth.

Podocarpium (Benth.) Y.C.Yang & P.H.Huang, Bull. Bot. Lab. N.-E. Forest. Inst., Harbin 4: 1. 1979, non Podocarpium A.Braun nec Podocarpium Unger.

Papilionopsis Steenis, Nova Guinea, Bot. 3: 17. 1960. Type species: P. stylidioides Steenis, nom. rej.

H. repandum (Vahl) H.Ohashi & R.R. Mill, in Edinburgh J. Bot. 57: 185. 2000. Hedysarum repandum Vahl, in Symb. Bot. 2: 82. 1791. Desmodium repandum (Vahl) Poir., in G.-F. Cuvier, Dict. Sci. Nat., ed. 2. 13: 109. 1819. Meibomia repanda (Vahl) Kuntze, in Revis. Gen. Pl. 1: 197. 1891. Podocarpium repandum (Vahl) Yen C. Yang & P. H. Huang, in Bull. Bot. Lab. N. E Forest. Inst., Harbin 4: 13. 1971. Type: Yemen, ‘Habitat in Arabia’, 1763, Forsskal 1320 (Holotype: C barcode C10002349 [web!])

Perennial, straggly climbing woody herb up to 4 m high, creeping on the forest floor or herbaceous shrub about 3 ft high. Stems woody forming undergrowth, brown to reddish, uncinulate-puberulent and moderately to sparsely pilose. Leaves trifoliolate; stipules brown, scarious, oblong to attenuate, 2–10 × 2–5 mm, puberulent and long pilose on the outer surface usually persistent; petiole linear, puberulent and pilose, 15–86 mm long; leaflets 16–124 × 8–72 mm, ovate or rhombic in shape, acute or pointed at apex, rounded or cuneate at base, entire to wavy or undulate margin, pilose with long and short hairs intermixed on both surfaces. Inflorescence a lax, axillary or terminal raceme, rarely panicle, 67–199 mm long. Flowers large and conspicuous; pedicel slender, 2–4 mm long; primary bracts each subtending 2–5 pedicels, 3.5–10 × 2–5 mm, elliptic to ovate-lanceolate; secondary bracts very small. Calyx triangular or lanceolate in shape, the upper pair joined to form an acute 2-fid lip, puberulent and pilose on teeth of both lobes. Standard orbicular or broadly elliptic, short-clawed. Wing petals narrowly elliptic or oblong, long auricled and short-clawed. Keel petals elliptic, obtuse at apex and clawed. Loments stipitate, upper suture straight and lower suture deeply indented, 4–8-articled; articles with straight appressed hairs on the surfaces, 5–7.5 × 2–3.5 mm. Stamens 10, monadelphous, with tube-like filaments.

Phenology: Flowering from December to June.

Diagnostic character: H. repandum is similar to D. intortum by growth habit, leaflet shape and inflorescence type, but markedly differs by its leaflets, which slightly undulate along the margin, and its stipule shape, which is oblong to attenuate vs. ovate-acuminate in D. intortum

Distribution: H. repandum is distributed in Taraba State in North-East Nigeria and Calabar State in South-South Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA. Taraba State: Mayo-Ndaga Village Forest, 16 January 1976, Latilo 116 (FHI); Along stream, 8 April 1970, Olorunfemi 194 (FHI); Gembu Forest Reserve, 8 January 1976, Ekwuno 291 (FHI); Gembu Forest Reserve, 12 February 1976, Ekwuno 212 (FHI); Gembu Forest Reserve, 22 January 1969, Daramola 142 (FHI). SOUTH-SOUTH NIGERIA. Cross-River State: Obudu cattle ranch, 29 October 1980, Gbile 40 (FHI); Obudu cattle ranch, 13 March 2002, Odewo 18 (FHI); O.C.R Hill, 22 July 2003, Odewo 42 (FHI); Obudu cattle ranch, Ogoja, 18 August 1973, Medlar 906 (IFE); Obudu cattle ranch, Ogoja, 27 September 1973, Medlar 972 (IFE).

3.6. Sohmaea H.Ohashi & K.Ohashi

Sohmaea H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(3): 159. 2018. Type species: Sohmaea laxiflora (DC.) H.Ohashi & K.Ohashi.

Uraria subgen. Desmodiastrum Schindl., in Repert. Spec. Nov. Regni Veg. 21: 15 1925). Type species: Uraria henryi Schindl.

Desmodium sect. Angustistipulosa H.Ohashi in Ginkgoana 1: 97. 1973. Type species: Desmodium laxiflorum DC.

S. laxiflora (DC.) H.Ohashi & K.Ohashi, in J. Jap. Bot. 93(3): 162. 2018. Desmodium laxiflorum DC., in Ann. Sci. Nat. (Paris) 4: 100. 1825. Meibomia laxiflora (DC.) Kuntze, in Revis. Gen. Pl. 1: 196. 1891. Type: Nepal, without date, Wallich s.n. (lectotype G barcode G00479839; isolectotypes: G barcode G00479877; G barcode G00479873, designated by Saisorn & Chantaranothai [28].

Erect herb or undershrub, 0.5–1.4 m high. Stems woody, angled, glabrous to appressed pubescent when young. Leaves trifoliolate, rarely unifoliolate, on lower part; stipules narrowly triangular, 2–6 × 0.5–2 mm; leaflets 17.0–107.0 × 14.0–85.0 mm, broadly ovate or ovate-elliptic in shape, acute at apex, rounded at base, entire at margin, glabrous and coriaceous above, grey and pubescent below, lateral vein conspicuous; petiole 2.50–8.70 cm long. Inflorescence a terminal or axillary raceme, rarely paniculate, 3.50–45.50 cm long; rachis pubescent with hooked hairs. Flowers pink, 3–6 flowered fascicles; pedicel 3–13 mm long, sparsely pubescent and densely uncinate; bracteoles absent; primary bracts, linear to ovate, surface pubescent, 2–5 mm long, subtending 3–6 flowers; secondary bracts narrowly triangular to linear, glabrescent to pubescent. Calyx 4-lobed, adaxial lobes connate almost entirely, teeth slightly exceeding the tube, outside pubescent, inside glabrous, 15–30 mm long. Standard broadly obovate or orbicular, apex emarginated, base attenuate, not auriculate and clawed, 2–5 mm long. Wing petals blue, oblong, apex obtuse, base auriculate and clawed, 2–6 × 1.5–3.5 mm. Keel petals blue, narrowly oblong, curved, apex acute, base not auriculate and clawed (Figure 5). Loments oblong-elliptic, green, 9–29 × 0.5–2 mm, 5–8 articled; articles indehiscent, pubescent with hooked hairs; both sutures straight or nearly so, with weak or slight constrictions between articles.

Phenology: Flowering from August to October and fruiting from October to November.

Diagnostic characters: S. laxiflora is distinguished from D. scorpiurus by stipule shape (narrowly triangular vs. obliquely ovate) and by articles that are oblong-elliptic; both sutures are nearly unconstricted between articles vs. narrowly elliptic in bead form and indented on both sides in D. scorpiurus.

Distribution: S. laxiflora is found only in North Central Nigeria in Minna, Ilorin, Lafia, and Makurdi.

Additional specimens examined: NORTH CENTRAL NIGERIA. Kwara State: Benue State: Markudi road, 10 October 1973, Hall 75 (UIH); Wildlife School Site Natural Reserve, 10 October 1979, Gbile 220 (FHI). Nasarawa State: Lafia division, 17 October 1973, Hall 732 (UIH). Niger State: Niger Forest Reserve, August 1957, Hepper 967 (FHI); West of Regina Village, 9 December 1970, Gbile 91 (FHI).

3.7. Polhillides H.Ohashi & K.Ohashi

Polhillides H.Ohashi & K.Ohashi, in J. Jap. Bot. 94(2): 71. 2019. Type Polhillides velutina (Willd.) H.Ohashi & K.Ohashi

P. velutina (Willd.) H.Ohashi & K.Ohashi, in J. Jap. Bot. 94 (2): 72. 2019. Hedysarum velutinum Willd., in Sp. Pl., ed. 4. 3: 1174. 1802. Desmodium velutinum (Willd.) DC., in Prodr. 2: 328. 1825; Schub., in Fl. Congo Belge et Ruanda-Urundi. 5: 194 1954; Hepper in Fl. West. Trop. Afr., ed. 2 [Hutchinson & Dalziel] 1: 584. 1958; Schub., in Journ. Arn. Arb. 44: 292. 1963. Meibomia velutina (Willd.) Kuntze, in Revis. Gen Pl. 1: 198. 1891. Type: America, without date, Herb. Willdenow 13763 (Holotype: B-W 13763 [Web!]).

Erect, woody, perennial herb or undershrub up to 4 m high. Stems branched, densely uncinulate-pubescent. Leaves 1-foliolate; stipules brown, long persistent, ovate-attenuate, 2.0–6.0 × 1.0–3.0 mm, pilose on the outer surface, ciliate; petiole sulcate, linear, densely strigose to glabrescent; leaflets 25–85 × 15–75 mm, rhombic-ovate, rounded at apex, cuneate at base, slightly wavy to entire at margin, ciliate, densely appressed pilose above, velvety beneath. Inflorescence terminal and axillary pseudoraceme, 21–180 mm long. Flowers small, pink, violet, purple, appearing whitish when dry; pedicel uncinulate-pubescent intersperse with straight hairs, 2–5 mm long, occasionally small bracteoles present on the pedicels; primary bracts, persistent, lanceolate to ovate-attenuate, pilose on the outer surface each subtending 3–5 pedicels, 1–3 × 0.5–1 mm; secondary bracts 1–1.5 mm long, linear, persistent. Calyx covered with stiff, straight, appressed hair. Standard obovate, retuse at apex, cuneate at base, varying in colour from red, violet, blue or lilac, 2.0–7.0 × 3.0–5.5 mm. Wing petals darker mauve, oblong, short-clawed, 2–5 × 1–3 mm. Keel petals blue, scythe shaped and clawed (Figure 6). Loments sessile to shortly stipitate, style usually persistent, 3–6-articled, Upper suture essentially straight to slightly curved, shallowly indented at the between the articles; lower suture ± rounded and distinctly indented at between the articles; articles uncinulate-pubescent interspersed with straight hairs.

Phenology: Flowering and fruiting from October to February.

Diagnostic characters: P. velutina is similar to P. gangeticus in growth habit and leaf type but can be distinguished by its tomentose on both surfaces, with nerves beneath with brown indumentum and velutinous. It can be distinguished from other species by its subpyramidal panicle inflorescence and jointed pods.

Distribution: P. velutina is a widespread species found in all six geopolitical zones in Nigeria.

Additional specimens examined: NORTH-EAST NIGERIA. Gombe State: Command Forest area, 16 November 1968, Lowe 1548 (UIH). Taraba State: Baissa Forest Reserve, 17 March 1980, Ekwuno 51 (FHI); Jos-Bauchi Road, 4 November 1980, Olorunfemi 84 (FHI). NORTH-WEST NIGERIA. Kaduna State: Ilabama Forest reserve, 12 December 1966, Daramola 124 (FHI). NORTH CENTRAL NIGERIA. Federal Capital Territory: Abuja, 1 June 1971, Owoseye 37 (IFE). Kogi State: Patt ridge, 4 July 1954, Keay 024 (FHI); Atodai Igala, 29 March 2001, Daramola 130 (IFE). Kwara State: Lafiagi Forest Reserve, 5 October 1976, Olorunfemi 425 (FHI); Ndeji Forest Reserve, 30 September 1976, Olorunfemi 124 (FHI); Kabba-Ogidi Road, 3 October 1978, Olorunfemi 213 (FHI); Erin-Ile, 16 September 1976, Latilo 89 (FHI); Wildlife School Site Natural Reserve, 10 October 1979, Olorunfemi 217 (FHI); Babana, 16 January 1973, Latilo 56 (FHI); Banaba, 17 December 1972, Latilo 24 (UIH). Nasarawa State: Keffi, 3 January 1971, Owoseye 157 (IFE). Niger State: Agaie-Baro Road, 3 May 1977, Olorunfemi 91 (FHI); Along Isaka-Lapai road, 24 February 1977, Olorunfemi 52 (FHI); Gurara falls near Izom, 30 May 1977, Gbile 187 (FHI); Mokwa-New Busaa Road, 2 May 1977, Olorunfemi 08 (FHI); Mokwa-Kontagora, 14 September 1971, Lowe 15 (UIH); Bida pici village, 1 November 1981, Lowe 142 (UIH). Plateau State: Jos-Bauchi Road, 16 November 1965, Latilo 241 (FHI). SOUTH-WEST NIGERIA. Ogun State: Shala Egbado, 20 February 1973, Ekwuno 208 (UIH); Asero stadium Abeokuta, 22 December 1979, Inah 58 (UIH); Shala, 17 November 1974, Ekwuno 524 (FHI). Ondo State: Benin-Ore road, 7 February 1980, Inah 83 (UIH); Ilasofia near Ikare, 19 June 1978, Olorunfemi 309 (FHI); Iyere, 22 December 1977, Olorunfemi 23 (FHI). Osun State: Awo-ede, 19 November 2013, Omomoh 352 (IFE); Owode-Ede Road, 28 November 1981, Ariwaodo 169 (FHI); Iwo-Ejigbo road, 09 Aug 1980, Daramola 04 (FHI); Univ. of Ife campus 22 September 2000, Daramola sn (IFE). Oyo State: International Institute of tropical Agriculture road, 7 December 1971, Daramola 115 (FHI); Okeho, 2 August 1980, Daramola 68 (FHI); Forestry research Ibadan, 8 June 1972, Daramola 103 (FHI); University of Ibadan campus, 15 February 1982, Afolayan 136 (UIH); University of Ibadan campus, 24 November 1979, Inah 55 (UIH); Path near Forestry school, 06 Oct 1971, Olorunfemi 741 (FHI); Along Oyo road IITA, 3 January 1980, Inah 81 (UIH); Okeho, 17 June 1977, Daramola 508 (FHI); Idere hill, 3 July 1979, Odewo 62 (FHI); Cattle ranch Iseyin, 28 February 1984, Odewo 122 (FHI); Old Oyo Game Reserve, 22 December 1977, Daramola 424 (FHI); Oyo road Obatedo village, 8 March 1985, Ibhanesebhor 101 (FHI); Ibadan-Ife road, 4 December 1991, Ibhanesebhor 07 (FHI); Igbetti road, Ogbomosho, 11 May 1971, Medley 15 (IFE); Oyo town, 24 November 1975, Olowu 11 (IFE); Moor plantation Ibadan, March 1965, Guile 811 (IFE); Near Iwo, 28 November 1974, Faremi 502 (IFE); Off Ojo village, Ibadan, 3 December 1968, Ogunremi 13 (IFE); Ogba river Okeho road, 15 October 1968, Olorunfemi 455 (IFE); Bodija Ibadan, February 1966, Guile 813 (IFE); Fed. Agric. Moor Plantation, 24 January 1970, Adewole 23 (IFE); Bodija cattle yard, 31 October 1970, Lowe 137 (UIH); Ogba river Okeho road, 7 November 1980, Olorunfemi 142 (UIH); Eleyeile reservoir Ibadan, 17 February 1970, Lowe 2017 (UIH); Ibadan Niger College, 20 November 1960, Jackson 2496 (UIH); University of Ibadan campus, 10 October 1967, Geedhill 623 (UIH); University of Ibadan campus, 18 October 1976, Oyewole 210 (UIH); Oyo road, 20 October 1954, Lowe 54 (UIH); University of Ibadan campus, 1 December 1969, Lowe 91 (UIH) SOUTH-EAST NIGERIA. Enugu State: Milliken hill forest vegetation, 6 April 1976, Olorunfemi 844 (FHI); Ngwo Forest Reserve, 11 February 1974, Onyeachisim 89 (FHI). SOUTH-SOUTH NIGERIA. Cross-River State: Ogoja-Ikom Road, 2 May 1978, Emwiogbon 365 (FHI); University of Calabar campus, 22 October 1984, Lowe 414 (UIH); Ogoja-Obudu road, 9 February 1980, Inaah 85 (UIH); Cassava farm opposite Bekwarra school, 13 February 1980, Inah 73 (UIH); Abuochiche roadside, 13 February 1980, Inah 74 (UIH); Sankwala, 13 November 1981, Ekwuno 852 (FHI); Ntamanta-Ikom Forest Reserve, 1 May 1978, Emwiogbon 70 (FHI). Edo State: Uzea Forest Reserve, 28 February 1976, Gbile 317 (FHI); Along farmland Owan, 2 January 1977, Gbile 25 (FHI); Uzairuwe Auchi, 20 October 1969, Lowe 1846 (UIH); Uzairuwe Auchi, 30 October 1969, Lowe 11761 (IFE); Igara-Auchi, 21 October 1969, Lowe 1996 (UIH).

3.8. Insufficiently Known Species

The following taxa have been reported at various times as part of the Nigerian representatives of Desmodium s.l. in the literature. However, their occurrence in Nigeria is poorly documented.

• Grona schweinfurthii (Schindl.) H.Ohashi & K.Ohashi

Note: This species is known from only one record from northern Nigeria, which was collected in 1962 and deposited at K herbarium.

2.

Desmodium ospriostreblum Chiov.

Note: This species is known from only one record from northern Nigeria, which was collected in 1962 and deposited at K herbarium.

3.

Desmodium distortum J.F.Macbr.

Note: Desmodium distortum was introduced to Nigeria as specified on POWO. There are three records of preserved specimens on the Global Biodiversity Information Facility (GBIF), which were collected from the northern and western parts of Nigeria but deposited at the Naturalis Biodiversity Center.

4.

Desmodium procumbens (Mill.) Hitchc.

Desmodium procumbens was introduced to Nigeria as specified on Plants of the World Online (POWO). It has only one record of a preserved specimen collected from northern Nigeria and deposited at K herbarium.

5.

Desmodium uncinatum (Jacq.) DC.

Note: It is reported as introduced to Nigeria on POWO, but it has no record of collection.

4. Conclusions

This taxonomic synopsis provides an update on the Desmodium s.l. (tribe Desmodieae) in Nigeria, highlighting 19 species across six genera (Grona, Desmodium, Pleurolobus, Sohmaea, Polhillides, and Hylodesmum) and three introduced species (D. distortum J.F.Macbr., D. procumbens (Mill.) Hitch., and D. uncinatum (Jacq.) DC). The study identifies key diagnostic characters such as leaflet shape, stipule form, inflorescence type, and morphology of fruit articles, which effectively distinguish species of the genus in Nigeria. Through morphological diagnosis, identification keys, and specimen records, this study provides a baseline for future comprehensive taxonomic revision and conservation studies in the tribe Desmodieae in Nigeria.