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Communication

The Leaf Length-Width Method Is Applicable to Compound Leaves of Diverse Forms

by
Kohei Koyama
Faculty of Education, Hokkaido University of Education, Asahikawa Campus, Hokumoncho 9, Asahikawa 070-8621, Hokkaido, Japan
Agriculture 2026, 16(6), 671; https://doi.org/10.3390/agriculture16060671
Submission received: 9 January 2026 / Revised: 3 March 2026 / Accepted: 10 March 2026 / Published: 16 March 2026
(This article belongs to the Section Artificial Intelligence and Digital Agriculture)
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Abstract

To estimate leaf area, the length-width method, also called the Montgomery equation, has been widely used. It is an empirical formula stating that within a given species, the area of a leaf is proportional to the product of its length and width. Although the formula is known to be applicable to a variety of simple leaves and leaflets, its applicability to compound leaves has only been investigated on a limited range of leaf forms and economically important crops. In this study, we investigated whether this method is broadly applicable to compound leaves of diverse forms. We measured 20 compound-leaved species including various leaf shapes (ternate, biternate, triternate, palmate, pedate, and pinnate leaves) as well as life forms (trees, herbs, and woody and herbaceous lianas). Our data cover diverse taxa, including both Ranunculales and core eudicots (Fabales, Rosales, Fagales, Vitales, Apiales, Lamiales, Asterales, and Dipsacales). The results show that the length-width method is applicable to all types of compound leaves investigated (slope [i.e., Montgomery parameter]: 0.298–1.035; R2 = 0.928–0.996). These results indicate that a compound leaf can be considered equivalent to a simple lobed leaf when applying the length-width method.

1. Introduction

Whole-plant leaf area determines the whole-plant photosynthetic rate and subsequent growth [1,2], which in turn determines crop yield [3,4,5,6]. In ecology, both single-leaf and whole-plant leaf area have been considered key traits that reflect adaptations to local environments [7,8,9,10]. Additionally, leaf size is regarded as an important trait that represents the position of each species within the leaf economics spectrum [11,12,13,14], reflecting a trade-off between resource acquisition and conservation [15,16,17,18,19,20]. Furthermore, at the ecosystem level, the leaf area index (LAI), defined as the total leaf area per unit of ground area, determines the ecosystem carbon uptake rate [21,22,23] (but see [24] for a counter-example), crop yield [25,26,27,28], water use efficiency [22,27,29], forest canopy rainfall redistribution [30], and the amount of litterfall [31], which drives the detritus food web [32]. To scale leaf-level physiological responses up to the ecosystem level, measurements of single leaf area are necessary [33,34]. Precise estimation of leaf area is therefore a crucial topic not only in basic plant science [35] but also in diverse fields of applied science, including agronomy [36,37,38,39], forestry [40,41,42], and urban greening technology [43,44,45,46].
The leaf length-width equation is an empirical equation stating that, within each species, individual leaf area is proportional to the product of its length and width. This equation, also called the Montgomery equation [47,48], has been applied to species from diverse taxa, such as magnoliids [49,50], monocots [49,50,51], eudicots [49,52,53] and ferns [49], including important food crops [47,54,55,56,57,58]. The basic idea underlying this equation is that different-sized leaves share the same basic form [50], allowing possible changes in their length-to-width ratio. Previous studies have shown that this equation is applicable to a variety of leaf shapes, such as lobed and/or dissected leaves [49] and/or bilaterally asymmetric leaves [48]. Additionally, this equation has been applied to tepals of flowers [59] and for insect wings [60]. Recent studies have further extended this equation to predict total leaf area per shoot [50,61,62,63,64], total petal area per flower [65], and total stomatal area per unit leaf area [66].
A major advantage of the length-width method is that it requires only a digital camera (including smartphones) and basic computer skills [67]. This simplicity stands in contrast to more advanced techniques that employ automated photography and/or image analysis (e.g., [68,69,70,71]). While these techniques offer higher throughput, they are more difficult to implement in general (but see [37,68]). Furthermore, leaves are three-dimensional objects (i.e., folded or curled) [72,73], and this 3D property poses difficulties for automated image extraction techniques that analyze only the projected area of leaves (e.g., [74]). Although several techniques can overcome this problem (e.g., [68,73,75,76,77,78,79,80,81,82,83]), they require either researcher-level programming skills (e.g., [73,83]) or elaborate photography setups such as fixing the camera at a particular angle and/or distance to the target leaves (e.g., [68,76,77,84,85,86,87]). Such requirements are often either expensive or difficult to implement for many researchers. For these reasons, to date, the length-width method remains widely used by field scientists as a complementary alternative to high-throughput image analysis.
A leaf that consists of multiple leaflets is called a compound leaf, which encompasses diverse forms [88,89,90,91,92]. The difference between simple and compound leaves with regard to resource investment in leaf lamina production and supportive structures has been an important topic in ecology [93,94]. Therefore, leaf area estimation techniques are essential not only for simple-leaved species but also for compound-leaved species in plant ecology. Despite its importance, however, the applicability of the leaf length-width equation to compound-leaved species has been investigated only for a limited number of economically important species (e.g., acacia (Acacia sp.) [95], soybean (Glycine max (L.) Merr.) [95,96,97], notoginseng (Panax notoginseng (Burkill) F.H. Chen ex C.Y. Wu & K.M. Feng) [90], raspberries (Rubus spp. [98]), roses (Rosa hybrid cultivars) [95,97], para rubber tree (Hevea brasiliensis (Willd. ex A.Juss.) Muell.Arg.) [99], potato (Solanum tuberosum L.) [100], tomato (Solanum lycopersicum L.) [101], and mahogany (Swietenia macrophylla King) [99]). However, information on wild species is still limited. Furthermore, the method has mainly been tested for a restricted range of leaf forms, such as ternate [96,99] or pinnate [95,99] leaves. Information is currently limited for palmate leaves (e.g., [90]) and other varieties of leaf forms (e.g., pedate, bipinnate, and tripinnate). Additionally, in many previous studies, the equation was applied only to leaflets (e.g., [49,102,103]) rather than to entire compound leaves. Therefore, the applicability of this equation to species with various leaf shapes and from diverse taxa has not yet been extensively studied. Previous studies showed that the length-width equation is applicable to lobed simple leaves [49,104]. Given this, we hypothesize that the equation can be applied to compound leaves as effectively as to simple leaves, if a compound leaf can be considered equivalent to a simple lobed leaf.

2. Materials and Methods

2.1. Study Species and Sampling

From 2022 to 2025, we measured 20 species covering various compound leaf forms, taxa, life forms, and leaf sizes (Table 1; Figure 1). Hereafter, each species is referred to by its genus name. A total of 735 leaves (sample size range: 30–52 leaves per species) were analyzed. Among them, three species (Fragaria, Lamprocapnos, and Rosa) were purchased from local stores as potted plants. Akebia and Causonis were sampled near the Taguri River in Sakura City. The site was located approximately 4 km from the AMeDAS Sakura Observatory (35°44′ N, 140°13′ E, altitude: 5 m a.s.l.) in Chiba Prefecture, which is in a warm temperate region in Japan. The mean annual temperature and precipitation from 1996 to 2025 (calculated by excluding the missing precipitation value for 1998) at the observatory were 15.10 °C and 1450 mm, respectively. Eleutherococcus and Sambucus were sampled in a forest at Kaguraoka Park (43°45′ N, 142°22′ E, 133 m a.s.l.) in Asahikawa City. The forest was a deciduous broad-leaved forest comprising alder (Alnus japonica (Thunb.) Steud.), elm (Ulmus davidiana Planch. var. japonica (Rehder) Nakai) and oaks (Quercus spp.). All other materials were sampled in and around the Hokkaido University of Education Asahikawa Campus (43°47′ N, 142°21′ E, 107 m a.s.l.) in Asahikawa City. The campus includes both natural vegetation (e.g., forests, wild plants) and artificially planted species (e.g., gardens, street trees). Except Dasiphora, the plants sampled in and around the campus were selected only from those growing naturally there. These two sites were within 4 km of the Asahikawa Local Meteorological Observatory (43°45′ N, 142°22′ E, 118 m a.s.l.), which is in a cool temperate region in Hokkaido, Japan. The mean annual temperature and precipitation from 1996 to 2025 at the observatory were 7.41 °C and 1114 mm, respectively. Weather data were obtained from the Japan Meteorological Agency (retrieved on 2 February 2026).
Our sampling strategy was not random; instead, the leaves were intentionally sampled to cover the full range of sizes within each species (i.e., small, medium and large leaves were selected as evenly as possible). We used only healthy, undamaged mature leaves. Immature leaves that had not fully expanded at the time of sampling were excluded. Because the leaves were selected based solely on their sizes, both sun and shade leaves were sampled without distinction, except for species found only in sunlit habitats (Causonis, Medicago, and Trifolium) or in partially shaded understories (Anemone, Corydalis, Eleutherococcus, and Sambucus). For purchased plants (Fragaria, Lamprocapnos, and Rosa), growth conditions, including temperature and light environments, were unknown. In the following analysis, all the leaves from different locations/individuals for each species were pooled and analyzed.

2.2. Leaf Size Measurement

We scanned the adaxial surfaces of the leaf laminas with flatbed digital scanners (A3 scanner 400-SCN025, Sanwa Supply, Okayama, Japan and A4 scanner PIXUS TS3530, Canon Inc., Tokyo, Japan) at a resolution of 600 dpi (Sorbus) or 300 dpi (all the other species) (Figure 1). When laminas were folded or curled, we stretched them out with small rectangular paper cards (30 mm × 68 mm, Tan-101-P, KOKUYO, Tokyo, Japan) during the scanning (see Figure 1). Additionally, when necessary, the same cards were placed to standardize the orientation of the leaflets. For four leaves of Juglans and Sambucus, which were larger than the A3 scanner, we photographed them with a digital camera by sandwiching leaves between transparent clear file folder sheets [67,105] (Figure 2).
We measured leaf size parameters following a free online manual of leaf measurement [67] by using the ImageJ (version 1.53a or 1.54g) [106]. The length of each compound leaf (Lleaf) was defined as the distance from the tip of the leaf to point P, which was the point where the most basal leaflet(s) were attached to the rachis (Figure 3). Leaf width (Wleaf) was defined as the distance between the tips of the pair of leaflets with the longest laminas [98] (Figure 3). Leaf area (Aleaf) was defined as the sum of the areas of the adaxial side of all the leaflet laminas plus the projected area of the rachis connecting them, excluding the basal part of the rachis that can be considered equivalent to the petiole (Figure 3). This exclusion was performed either by manually cutting this part with scissors before scanning (e.g., Figure 2a) or by manually masking the digital image of this part with the brightly colored “Paintbrush” tool of ImageJ after scanning (Figure 3c). The leaf area was measured after binarization of the image by using ImageJ (Figure 2b and Figure 3c). When necessary, the images were trimmed to facilitate binarization [67]. Except for these cases, no further manipulations (e.g., changing the contrast or brightness) were performed on the photographs prior to the measurements.

2.3. Data Analysis

Data analyses were performed using the statistical software R version 4.5.2 [107] with the packages ggplot2 [108], cowplot [109], and gridExtra [110]. We performed the ordinary least squares (OLS) linear regression. To choose between OLS and reduced major axis (RMA) regression, we followed the argument of Warton et al. [111]. The aim of the present regression analysis is to predict the dependent variable Y (leaf area) from the independent variable X (the product of leaf length and width). The choice of OLS is aimed at minimizing errors along the Y-axis, which is suitable for the present case. The parameters (the slope and intercept for each regression line) were calculated using the R function lm. When the intercept is sufficiently small, the slope can be considered the proportionality constant, also called the correction factor [49] or the Montgomery parameter (M) [48,62,63].

3. Results

The length–width equation was applicable to all investigated species (R2 = 0.928–0.996; p < 1.0 × 10−5 for all cases, Figure 4 and Figure 5 and Table 2). Because the intercepts were small, the slopes were regarded as the proportionality constants (i.e., the Montgomery parameter M). The observed values of M ranged from 0.298 (Bidens) to 1.03 (Trifolium).

4. Discussion

We demonstrated the applicability of the length-width method to compound leaves by investigating species with various leaf shapes from diverse taxa. The resultant values of M are within the range reported for simple leaves [49,67].
The homology between simple and compound leaves has long been debated [113,114], and whether a compound leaf is homologous to a single lobed leaf or to a shoot remains elusive [115,116]. Previous studies have shown that the length-width method is applicable to heavily lobed simple leaves [49,98,104]. Schrader et al. [49] found that, among simple-leaved species, the Montgomery parameter (M) is high for species with protruding leaves (i.e., leaves in which the lamina extends below the point of attachment to the petiole). Given their findings, we expected that M would be higher for strongly protruding leaves than for weakly protruding or non-protruding leaves. The higher value of M observed in protruding leaves of Trifolium (M > 1) than in other species in the same family, Fabaceae (in the order Fabales in Figure 5), is consistent with the previous findings for simple leaves [49]. In contrast, we found no phylogenetic trend in the M values. Instead, M varied greatly both within Fabales and Ranunculales (Figure 5). This indicates that leaf morphological variation within a single family has large effect on the value of M, which is consistent with the results for simple leaves [49]. These results indicate that a compound leaf can be considered analogous to a heavily lobed simple leaf, at least for practical purposes such as when using the length-width method. However, because we did not investigate the developmental origins of the leaflets in the present study, this interpretation should be viewed as a practical approximation without further developmental implications.
We excluded petioles or their equivalents when measuring leaf lengths (shown in Figure 3 as “not measured”). Note that this part may not be developmentally equivalent among different leaf forms. For a palmate leaf (Figure 3b), the excluded part can readily be considered the petiole. In contrast, for a pinnate leaf (Figure 3a), because its rachis cannot be distinctly separated into a midvein and a petiole, this excluded part is not biologically equivalent to that of a palmate leaf. We used this definition because this petiole-equivalent portion is analogous to the petiole of a simple leaf of some species, the petiole of which indistinctly merges into the midvein, such as the lobed leaves of Artemisia sp. (see a photograph in ref. [67]). Alternatively, we could have applied different definitions of leaf length (and leaf width, as well) by taking species-specific morphology into consideration. However, this would present another disadvantage for users of this equation, because a species-specific definition of length/width would be required to apply the equation to each new species. Hence, we believe that using a single, consistent definition is more reproducible and, thus, more useful for users of this equation, at least for practical purposes. Nevertheless, this interpretation should be viewed as a practical approximation without further developmental implications.
We did not control the environmental or developmental conditions of the plant materials (e.g., leaves were sampled from both field-grown plants and potted plants, as well as from both young and adult plants), because our aim was to test the generality of the length-width method. However, as the present study investigated only species from temperate regions, further studies including species from different climates, such as the tropics, subtropics, and arid regions, are required.

5. Conclusions

The leaf length-width method, also referred to as the Montgomery equation, is applicable not only to simple leaves or leaflets but also to compound leaves. Our findings indicate that a compound leaf can be considered equivalent to a single heavily lobed leaf, at least when estimating leaf area using the length-width equation.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/agriculture16060671/s1.

Funding

This research was funded by the JSPS KAKENHI Grant Number 23K05931.

Institutional Review Board Statement

Not applicable.

Data Availability Statement

All the dataset are available in the Supplementary Materials.

Acknowledgments

We thank Asahikawa City Office, the Asahikawa River Office of Asahikawa Development and Construction Department of the Hokkaido Regional Development Bureau, and Hokkaido University of Education for providing permission for samplings at the study sites. We also thank Masatoshi Sato for useful comments on species identification.

Conflicts of Interest

The author declares no conflicts of interest.

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Figure 1. Scanned leaf images. Ternate leaves of (a) Amphicarpaea edgeworthii Benth., (b) Cryptotaenia japonica Hassk., (c) Fragaria vesca L., (d) Medicago sativa L., and (e) Trifolium repens L. A biternate leaf of (f) Anemone raddeana Regel. A triternate leaf of (g) Corydalis incisa (Thunb.) Pers. A biternate leaf of (h) Lamprocapnos spectabilis Fukuhara. Palmate leaves of (i) Akebia quinata Decne., (j) Eleutherococcus divaricatus (Siebold & Zucc.) S.Y.Hu, and (k) Parthenocissus quinquefolia Planch. A pedate leaf of (l) Causonis japonica (Thunb.) Raf. Pinnate leaves of (m) Bidens frondosa L., (n) Dasiphora fruticosa (L.) Rydb., (o) Fraxinus mandshurica Rupr., (p) Juglans mandshurica var. sachalinensis (Komatsu) Kitam., (q) Robinia pseudoacacia L., (r) Rosa hybrid cultivar, (s) Sorbus commixta Hedl., and (t) Sambucus racemosa L. subsp. kamtschatica (E.L. Wolf) Hultén. Large white papers were placed as backgrounds. Small rectangular paper cards (30 mm × 68 mm) were placed to stretch out the laminas and as scales. The images scanned from 2022 to 2025 by Kohei Koyama.
Figure 1. Scanned leaf images. Ternate leaves of (a) Amphicarpaea edgeworthii Benth., (b) Cryptotaenia japonica Hassk., (c) Fragaria vesca L., (d) Medicago sativa L., and (e) Trifolium repens L. A biternate leaf of (f) Anemone raddeana Regel. A triternate leaf of (g) Corydalis incisa (Thunb.) Pers. A biternate leaf of (h) Lamprocapnos spectabilis Fukuhara. Palmate leaves of (i) Akebia quinata Decne., (j) Eleutherococcus divaricatus (Siebold & Zucc.) S.Y.Hu, and (k) Parthenocissus quinquefolia Planch. A pedate leaf of (l) Causonis japonica (Thunb.) Raf. Pinnate leaves of (m) Bidens frondosa L., (n) Dasiphora fruticosa (L.) Rydb., (o) Fraxinus mandshurica Rupr., (p) Juglans mandshurica var. sachalinensis (Komatsu) Kitam., (q) Robinia pseudoacacia L., (r) Rosa hybrid cultivar, (s) Sorbus commixta Hedl., and (t) Sambucus racemosa L. subsp. kamtschatica (E.L. Wolf) Hultén. Large white papers were placed as backgrounds. Small rectangular paper cards (30 mm × 68 mm) were placed to stretch out the laminas and as scales. The images scanned from 2022 to 2025 by Kohei Koyama.
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Figure 2. (a) A pinnately compound leaf of Sambucus racemosa subsp. kamtschatica (E.L. Wolf) Hultén sandwiched between transparent clear file folder sheets. (b) The binarized image for the area measurement. The photograph taken on 18 July 2024 by Kohei Koyama.
Figure 2. (a) A pinnately compound leaf of Sambucus racemosa subsp. kamtschatica (E.L. Wolf) Hultén sandwiched between transparent clear file folder sheets. (b) The binarized image for the area measurement. The photograph taken on 18 July 2024 by Kohei Koyama.
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Figure 3. Definitions of compound leaf length (Lleaf) and width (Wleaf) illustrated on leaves of (a) walnut (Juglans mandshurica var. sachalinensis (Komatsu) Kitam.) and (b) Eleutherococcus divaricatus (Siebold & Zucc.) S.Y.Hu. (c) A leaf of alfalfa (Medicago sativa L.) before and after binarization, with the petiole-equivalent part manually cut off using the Paintbrush tool of ImageJ (indicated by the small yellow line). Images scanned from 2023 to 2025 by Kohei Koyama.
Figure 3. Definitions of compound leaf length (Lleaf) and width (Wleaf) illustrated on leaves of (a) walnut (Juglans mandshurica var. sachalinensis (Komatsu) Kitam.) and (b) Eleutherococcus divaricatus (Siebold & Zucc.) S.Y.Hu. (c) A leaf of alfalfa (Medicago sativa L.) before and after binarization, with the petiole-equivalent part manually cut off using the Paintbrush tool of ImageJ (indicated by the small yellow line). Images scanned from 2023 to 2025 by Kohei Koyama.
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Figure 4. Compound leaf area is proportional to the product of the leaf length and the width. Each panel shows OLS (ordinary least square) linear regression line for one species shown with its genus name (p < 1.0 × 10−5 for all cases). Within each panel, each closed circle indicates one leaf.
Figure 4. Compound leaf area is proportional to the product of the leaf length and the width. Each panel shows OLS (ordinary least square) linear regression line for one species shown with its genus name (p < 1.0 × 10−5 for all cases). Within each panel, each closed circle indicates one leaf.
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Figure 5. The values of the Montgomery parameters are shown in red. The phylogeny is based on APG IV [112].
Figure 5. The values of the Montgomery parameters are shown in red. The phylogeny is based on APG IV [112].
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Table 1. List of the study species.
Table 1. List of the study species.
Panel in Figure 1Species NameLeaf Shape *1OrderLife Form:
H (Herbaceous), W (Woody)		N *2
aAmphicarpaea edgeworthii Benth.C3FabalesH (liana)40
bCryptotaenia japonica Hassk.C3ApialesH34
cFragaria vesca L.C3RosalesH34
dMedicago sativa L.C3FabalesH37
eTrifolium repens L.C3FabalesH33
fAnemone raddeana RegelC3 × 2RanunculalesH31
gCorydalis incisa (Thunb.) Pers.C3 × 2 or C3 × 3RanunculalesH30
hLamprocapnos spectabilis FukuharaC3 × 2RanunculalesH43
iAkebia quinata Decne.C5RanunculalesW (liana)31
jEleutherococcus divaricatus (Siebold & Zucc.) S.Y.HuC5ApialesW44
kParthenocissus quinquefolia Planch.C5VitalesW (liana)40
lCausonis japonica (Thunb.) Raf.E5VitalesH (liana)31
mBidens frondosa L.PAsteralesH38
nDasiphora fruticosa (L.) Rydb.PRosalesW47
oFraxinus mandshurica Rupr.PLamialesW31
pJuglans mandshurica var. sachalinensis (Komatsu) Kitam.PFagalesW35
qRobinia pseudoacacia L.PFabalesW35
rRosa hybrid cultivarPRosalesW52
sSorbus commixta Hedl.PRosalesW35
tSambucus racemosa L. subsp. kamtschatica (E.L.Wolf) HulténPDipsacalesW34
*1 C3: ternate; C3 × 2 biternate; C3 × 3 triternate; C5 palmate, specifically with five leaflets; E5; pedate, specifically with five leaflets; P: pinnate. *2 N: Total number of leaves analyzed.
Table 2. OLS (ordinary least square) linear regression results.
Table 2. OLS (ordinary least square) linear regression results.
Species (Genus Name)Compound Leaf Area (cm2)Linear Regression Y = a + bX
(Y = Leaf Area, X = The Product of Leaf Length and Width)		R2 *1
MinMaxIntercept (a) (cm2)Slope (b) = Montgomery Parameter (M)
Amphicarpaea1.09282935647.674313250.2234211240.5211994550.991167156
Cryptotaenia1.90702127697.351704940.752026450.6248064060.992174317
Fragaria0.66265100425.9248227−0.3308685690.7439200920.995928821
Medicago0.5651601616.410218080.7868610320.4321752760.978632608
Trifolium0.58924613323.72812459−0.1750194621.0348699910.99402099
Anemone0.48845780491.793078061.6867651930.5982025250.953724822
Corydalis1.7619319658.266980240.1592018430.5675371990.973812028
Lamprocapnos0.514049151100.09478192.4659914730.4312313940.970151587
Akebia2.36995941841.411960191.2690870090.6266166750.962310559
Eleutherococcus8.749588236230.39545323.139634360.5611234120.99016514
Parthenocissus9.124927987376.0823303−16.703586620.6886288410.9825661
Causonis4.91654930765.4376469−1.2772236620.584298430.978485828
Bidens1.17533815182.172093720.1148133930.2982875250.956290676
Dasiphora0.19512505810.88779184−0.2289734810.5336330810.963685501
Fraxinus22.07135371540.8598502−0.1613172010.5252144070.959637716
Juglans15.229431911198.6427550.0900646910.4802155370.990763168
Robinia9.942274022343.1277725−16.980463350.6819894670.989376056
Rosa0.3624365519.6057155560.4174379250.4033257920.927692969
Sorbus11.03424316148.53588570.6220959110.4045862030.967762119
Sambucus24.20948563521.0701433−15.319127780.509374970.981410065
*1 Adjusted R-squared values. Full dataset (including leaf length, width, and area for each leaf) is available in the Supplementary Materials.
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Koyama, K. The Leaf Length-Width Method Is Applicable to Compound Leaves of Diverse Forms. Agriculture 2026, 16, 671. https://doi.org/10.3390/agriculture16060671

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Koyama K. The Leaf Length-Width Method Is Applicable to Compound Leaves of Diverse Forms. Agriculture. 2026; 16(6):671. https://doi.org/10.3390/agriculture16060671

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Koyama, Kohei. 2026. "The Leaf Length-Width Method Is Applicable to Compound Leaves of Diverse Forms" Agriculture 16, no. 6: 671. https://doi.org/10.3390/agriculture16060671

APA Style

Koyama, K. (2026). The Leaf Length-Width Method Is Applicable to Compound Leaves of Diverse Forms. Agriculture, 16(6), 671. https://doi.org/10.3390/agriculture16060671

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