Disentangling Taxonomic Complexity in the Native Range: Morphological and Genetic Differentiation Among Subspecies of Taeniatherum caput-medusae (Poaceae)
, James F. Smith 1, Marcelo D. Serpe 1 and Stephen J. Novak 1,*Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe autors presented interestng paper showing morphological and genetic differentiation among Subspecies of Taeniatherum caput-medusae. The paper is based on previous studies particularlay Frederiksen 1986 and Frederiksen and von Bothmer 1986. Overall, the MS is well written and organized and merit to be published.
I have some comments in the attached file.
Comments for author File: 
Comments.pdf
Author Response
"Please see the attachment."
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis study tried to differentiate the three subspecies of T. caput-medusae by morphological and genetic difference. Results showed that glume length, glume angle, and palea length were significant different among three subspecies. Genetic analysis showed that subspecies crinitum is genetically differentiated from the other two subspecies, and the other two subspecies asperum is the most variable. After carefully reading the paper, I found some shortcomings that may affect the robust of the results.
1. This paper makes morphological and genetic comparisons among the 3 subspecies. I wonder how these 3 subspecies were distinguished before the performance of this study and whether there is already a clear way to distinguish them. If so, then the significance of this study will be diminished.
2. This paper used samples from common garden experiment to compare the morphological characteristics of the three subspecies, rather than direct field sampling. Since invasive plants usually have high phenotypic plasticity, I am concerned that the common garden experiment would affect the morphological results.
3. Introduction: since the 3 subspecies are so similar, why did only asperum invade in US? And why the 3 subspecies dominated in different area in native range? More information should be provided.
4. Line 112, what does “this research program” mean? This study did not relate with the genetic and evolutionary consequences of the introduction of T. caput-medusae into the western U.S.
Author Response
"Please see the attachment."
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsI have read the manuscript "Disentangling Taxonomic Complexity in the Native Range: 2 Morphological and Genetic Differentiation Among Subspecies 3 of Taeniatherum caput-medusae" by Hinkle and co-authors.
The topic of the paper is very interesting and the general introduction is perhaps well written and can resemble a review. However, I have serious concerns about the manuscript from the second part of the introduction. In fact, the taxonomic aspect of the issue has not been properly addressed. Many more references would be needed, illustrating divergent treatments by different scholars. For example, the three subspecies are not accepted by many authors nowadays and in fact the obscure geographical segregations and especially the presence of different presumed subspecies in the same place cast doubt that we observe only a continuous variation between two extremes of variability. A more complex scenario would require a more robust investigation with modern methodology.
Especially in the case of molecular analyses applied to weakly differentiated taxa, as in this case, the old techniques may be not able to produce satisfactory results. With regard to morphometry, Cluster Analysis is often considered a only a better presentation of the data, but without effective resolving. However, even accepting this analysis, the shown dendrogram is far from suggesting a convincing separation between the three putative subspecies. Scatter plots are also ineffective. Why did the authors not use more powerful and appropriate means to test biological complexity but ANOVA? Overall, did they test whether the three surviving characters are correlated among them? Including correlated variables in the same analysis can be misleading, artificially inflating the putative differences between taxa. Since the authors have collected a lot of information, I expect they will have little difficulty in repeating the morphometric analyses according to modern and widely accepted methods.
In the Discussion, almost no words were spent on the main stated purposes and consequences of this study for the management of Taeniatherum. I suggest to reduce the parte related to the biological invasion aspect and refocuse the controibution on the taxonomic aspect, which must be, however, imrpoved.
The quality of illustration is low. Minor remarks in the attached file.
Comments for author File: Comments.pdf
Author Response
"Please see the attachment."
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe author has made corresponding revisions based on my suggestions. There is only one minor comment. In general, in figure 2, the bar with the largest mean value will be marked with A.
Author Response
Reviewer Comment: The author has made corresponding revisions based on my suggestions. There is only one minor comment. In general, in figure 2, the bar with the largest mean value will be marked with A.
Author response: Done
