Senna demissa var. radicans (H.S.Irwin & Barneby) H.S.Irwin & Barneby

Authors

Howard S. Irwin, Rupert C. Barneby

Authority

Irwin, Howard S. & Barneby, Rupert C. 1982. The American Cassiinae. A synoptical revision of Leguminosae tribe Cassieae subtrib Cassiinae in the New World. Mem. New York Bot. Gard. 35, part 1: 1-454.

Family

Caesalpiniaceae

Scientific Name

Senna demissa var. radicans (H.S.Irwin & Barneby) H.S.Irwin & Barneby

Type

Holotypus, TEX! isotypus, GH!

Synonyms

Cassia demissa var. radicans H.S.Irwin & Barneby

Description

Variety Description - As described in key. [Key: "Stems decumbent from a loosely branched, often adventitiously rooting caudex, at anthesis 1-3.5 dm, pilose-pilosulous with spreading-ascending or horizontal hairs up to 0.8-2 mm; relatively widespread in centr. and s.-e. Coahuila, disjunct in s.-w. Tamaulipas."]—Collections: 11.

Distribution and Ecology - Hillsides and canyons, in izotal and chaparral and ascending into pinyon woodland, 1400-2100 m, scattered through the mountains of centr. and s. Coahuila from Sa. de la Madera s. through Sas. de Fragua and de Organos to Sa. de Parras and the Sa. Madre immediately s.-e. of Saltillo; collected once in s.-w. Tamaulipas, close to a population of S. crotalarioides, and perhaps there intergradient.— Fl. VI-IX.

Discussion

The earliest collection of var. radicans, Gregg 244. was misidentified by Bentham (1871, p. 530) as Cassia vogeliana, i.e. the setose aspect of S. crotalarioides. The second, Palmer 281, contributed to Rose’s original concept of C. demissa. We here give var. radicans precedence over the rarer and, we suspect, more derived var. demissa, which represents the pygmy extreme of its group.

Distribution

Coahuila Mexico North America| Tamaulipas Mexico North America|