Studies in the GenusDyschoriste(Acanthaceae): I. Plants of Northern Mexico, Texas to Arizona

A systematic treatment of Dyschoriste (Acanthaceae) of northern Mexico, Arizona, and Texas is provided. The taxa show few unique characteristics; taxonomy is largely based on differences in vestiture and growth habit; intergradation is widespread. Five species are recognized: (1) D. schiedeana with four intergrading varieties, var. schiedeana, var. cinerascens, var. decumbens, and var. prostrata, of central-northern Mexico north to trans-Pecos Texas and Arizona; (2) D. linearis var. linearis and var. sanpatriciensis of Texas; (3) D. crenulata, of the Big Bend area and southmost Texas and adjacent Mexico; (4) D. poliodes var. poliodes, var. obispoensis, and var. glabra; and (5) D. greenmanii of Nuevo León and Tamaulipas. Keys and descriptions are provided.