A biosystematic study of the Schizachyrium cirratum - Schizachyrium sanguineum complex (Poaceae)

Abstract

A taxonomic investigation of the Schizachyrium cirratum - Schizachyrium sanguineum complex was made. The following taxa were included: S. cirratum, S. hirtiflorum, S. sanguineum, and S. semiberbe. The above taxa were compared with S. scoparium var. neomexicanum which is similar morphologically. Two varieties were delimited in S. cirratum, S. cirratum var. cirratum and S. cirratum var. mexicanum. The remaining taxa, excluding S. scoparium var. neomexicanum, were included in one species, S. sanguineum with three varieties, S. sanguineum var. sanguineum, S. sanguineum var. domingense, and S. sanguineum var. oligostachyum. Anatomical studies did not provide any new character combination to delimit the taxa. The culms had solid internodes with three peripheral rings of vascular bundles. Transverse sections of the leaf showed approximately a 3:1 ratio of minor to major vascular bundles, radiating chlorenchyma, a single bundle sheath per vascular bundle, and bulliform cells in groups of 4-7. The epidermis was typical panicoid, with macro and microhairs, low-dome shaped or triangular subsidiary cells, short cells dumbell or cross shaped or occasionally nodular, and short cells in rows of 2- many. ...