Background:

Verbesina molinaria B.L. Rob. & Greenm. and V. oncophora B.L. Rob. & Seaton constitute species with conflicting circumscription; different authors consider them as two different or just one species (V. oncophora).

Questions:

¿Are they one or two species of Verbesina? ¿A linear discriminant analysis (LDA) will differentiate them as two species?

Species studied/Mathematic model:

Verbesina molinaria and V. oncophora / Royston, Shapiro-Wilk, Levene, correlation (Pearson), Variance inflation factor (VIF), and LDA.

Study site and years:

Mexico; 2022-2023.

Methods:

Types, protologues, as well as herbarium specimens at ENCB, HUMO, MEXU, and UAMIZ of the two species were analyzed, assigning a preliminary name to each one. A data matrix with the characters and character states was created to carry out the statistical analyses. Box plots were generated to evaluate differences among characters and the statistical tests were done using the software Rstudio.

Results:

Types and protologs analyses revealed morphological differences between both species. Royston and Shapiro-Wilk tests supported normality among characters evaluated, and the Levene test suggests there are no significant differences among them. Finally, Pearson correlation and the VIF values suggested the absence of correlation or collinearity. The LDA analysis showed 100 % accuracy in the assigning of specimens to the a priori species allocated.

Conclusions:

The two species represent distinct taxa based on the morphological differences and statistical support, one of them widespread in central Mexico (V. oncophora) and the other (V. molinaria) restricted as far as now to the states of Mexico, Morelos, and Michoacán.

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