Reassessment of morphological species delimitations in the Cyperus margaritaceus-niveus complex using morphometrics.

Xanthos, Martin; Mayo, Simon J.; Larridon, Isabel

Reassessment of morphological species delimitations in the Cyperus margaritaceus-niveus complex using morphometrics.

Download

Name

s11557-023-01876-7__1_.pdf

Description

visibility:open

Size

4.04 MB

Format

Adobe PDF

Checksum (CRC64NVME)

RRgfqGm69wk=

Resource type

Journal article

Creator (person)

Xanthos, Martin

ORCID

Mayo, Simon J.

ORCID

Larridon, Isabel

ORCID

Date published

March 22, 2023

Abstract

– The complex is a group of ten tropical species from sub-Saharan Africa and Madagascar: , , , , , , , , , and . They are characterised by a capitate head of white-yellow spikelets and modified culm bases and recent molecular analysis puts them in a distinct clade. The group lacks a modern taxonomic revision, and the taxa described in the Flora treatments of the past 50 years differ considerably in their circumscription. In this study, morphometric analyses are used to test species limits to establish more stable morphological delimitations of the taxa. – An examination of 15 morphological characters on 489 herbarium specimens was carried out and the data was analysed using Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) with cross-validation, and Classification and Regression Tree (CART) analysis. was not further considered due to lack of material. – Both PCA and LDA showed varying degrees of overlap in the nine remaining taxa, with no single group clearly separating in multivariate space. However, cross-validation clearly showed as a distinct entity despite its overwhelming presence in the PCA. Both LDA and CART failed to separate as a distinct group as its specimens were dispersed among the other groups. Differing results were obtained for other taxa depending on the type of analysis. , , and were divided into two groups by CART but re-examination of the specimens does not definitively support the idea that these infraspecific groups represent separate taxa. – The results show that eight morphospecies are recognised by LDA and six morphospecies by CART. Characters used to separate the taxa in Flora treatments scored high loadings in the analysis showing their high taxonomic utility value. The methods used can be applied to resolving other complexes in the Cyperaceae.