Species delimitation in the Sporobolus aeneus complex (Zoysieae, Chloridoideae, Poaceae) using the phylogenetic species concept

DENHAM S. S.; ALISCIONI S. S.

TAXON

INT ASSOC PLANT TAXONOMY

Lugar: Vienna; Año: 2010 vol. 59 p. 1765 - 1782

0040-0262

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Abstract. The “Sporobolus aeneus complex” constitutes a morphologically well-defined group of species with lax, exerted, pyramidal panicles with verticillate branches. It comprises 14 species and six infraspecific taxa growing in southern South America, including eastern Bolivia, eastern Paraguay, Uruguay, southern Brazil, and northeastern Argentina (except for a more widespread species, S. cubensis). Many authors recognized the affinity among species of the complex but, as studied partially in regional floras, species delimitation considering all of them remain unresolved. To clarify the “Sporobolus aeneus complex” taxonomy, multivariate analyses of qualitative and quantitative characters taken from herbaria specimens were performed. We applied the phylogenetic species concept and we used a modified “population aggregation analysis.” Five species (S. aeneus, S. cubensis, S. linearifolius, S. multinodis, and S. recurvatus) are recognized by a unique combination of qualitative character states and three varieties are proposed based on significant mean value differences of quantitative characters. Type specimens and original descriptions were used to assign names and construct synonymies. We concluded that leaf blade pilosity, broadly used as a diagnostic character in the complex, is affected by external conditions like fire or blade age, resulting in an unreliable taxonomic character. Two new cominations, Sporobolus aeneus var. angustifolia (Döll) S. Denham & Aliscioni and S. aeneus var. eximius (Nees ex Trin.) S. Denham & Aliscioni are made. Vilfa acuminata Trin. and Vilfa eximia Nees ex Trin. are lectotypified.