Monographs Details: Senna guatemalensis var. oligantha 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.
Synonyms:Cassia guatemalensis Donn.Sm.
Description:Variety Description - Usually thinly pilosulous with narrowly ascending hairs, rarely loosely pilose, the longest hairs 0.5—1.1 mm; glands between first and second pairs of lfts; long lfts 3-6 x 1.3-2.8 cm, 2.1-2.7 times as long as wide; outer sepals 4-4.5 mm, the inner ones 5.5—6.5 mm; longer petals 10-11 mm; style 0.6-1.1(?-2) mm; pod as broad as that of var. guatemalensis but a little shorter, the stipe 3.5-7 mm.— Collections: 8. [Key: "Racemes 6-20-fld, the fruiting axis 1-3 cm; s.-w. Guatemala (Santa Rosa) to n.-w. Nicaragua (Jinotega)."]

Distribution and Ecology - Mixed montane rain forest, becoming abundant along roads and in newly cleared pasture, 1650-2250 m, scattered along the Cordilleras of s.-w. Guatemala (Sta. Rosa), El Salvador (Sta. Ana, Chalatenango), Honduras (Intibuca) and n.-w. Nicaragua (Jinotega).—Fl. IX-I.

Discussion:This seems clearly distinct from typical var. guatemalensis of the central and northwestern highlands of Guatemala in its fewer leaflets, short, relatively few- flowered racemes, and somewhat shorter pod. The earliest known collection, Heyde & Lux 4176, contributed something to the original concept of Cassia guatemalensis, but, as shown below, was not the crucial or diagnostic element. Poor flowering specimens from the Sierra Madre of Chiapas, (Siltepec, X, XI. 1940, fl, Matuda 4125, MICH, NY) agree in almost all details with var. oligantha, but the style is ±2 mm long, about twice the length observed in any other specimen of C. guatemalensis sens. lat. Until fruit can be obtained it seems prudent to postpone definite identification and the locality has not been included in our statment of range.
Distribution:Santa Rosa Guatemala Central America| Santa Ana El Salvador Central America| Chalatenango El Salvador Central America| Intibucá Honduras Central America| Jinotega Nicaragua Central America|