The genus Schizachyrium in Mexico and Central America

Vita.A systematic treatment of the genus Schizachyrium for Mexico and Central America is presented. Nine species are recognized for the area: S. brevifolium, S. cirratum, S. condensatum, S. gaumeri, S. salzmannii, S. sanguineum, S. scoparium, S. semitectum, and S. tenerum. Two varieties are recognized for S. scoparium: var. scoparium and var. littoralis. Schizachyrium muelleri is excluded and treated as Andropogon muelleri. Morphological analysis was based on the study of herbarium specimens and field studies, and is supplemented with a list of annotated specimens. Anatomical analysis was based on leaf blade micromorphology and is illustrated with drawings and photographs. Chromosome counts were investigated in the literature and corroborated as 2n = 20 for S. condensatum, 2n = 100 for S. sanguineum and 2n = 40 for S. scoparium. A chromosome number of n = 10 is reported for first time for S. salzmannii. The underground structure of the seedling was recorded for seven species. Elongation of the mesocotyl is present in S. condensatum and absent in S. brevifolium, S. salzmannii, S. sanguineum, S. scoparium, S. semitectum, and S. tenerum. The utility of ribosomal DNA analysis for systematic use in the Andropogoneae could not be assessed due to insufficient data. Information on methodology, protocols, and suggested modifications is provided