Senna spinescens var. schultesiana

Title

Senna spinescens var. schultesiana

Authors

Howard S. Irwin, Rupert C. Barneby

Scientific Name

Senna spinescens var. schultesiana H.S.Irwin & Barneby

Description

53b. Senna spinescens (Vogel) Irwin & Barneby var. schultesiana Irwin & Barneby, var. nov., a var. spinescente foliolis cum caulibus ubique molliter minutim pilosula (nec superne vel utrinque glabris), foliolorum pulvinulis abbreviatis 1.5-2.5 (nec 3-5.5) mm longis, antheris abaxi- alibus elongatis rostro excluso 15-20 (nec 7.5-13.5) mm usque longis, sepalis subaequilongis 6-8.5 tantum (nec 11-15 usque) mm longis, styloque saepissime longiori ac crassiori 1-2 x 0.7 (nec x0.4) mm abstans.—COLOMBIA. Vaupes: Rio Apoporis at Soratama (above mouth of Rio Kananari, ±270 m, 6.II.1952 (fl), Richard Evans Schultes & Isidoro Cabrera 15183.—Holotypus, US.

Characters as given in key and diagnosis.—Collections: 7.

Riparian forest, at least sometimes inundated at flood seasons, 170-270 m, along rios Apoporis and Vaupes (Caiari) in Comisaria de Vaupes, Colombia and on upper rios Negro and Vaupes in n.-w. Amazonas, Brazil.—Fl. I-IV.

Flowering specimens of var. schultesiana are sharply distinguished from var. spinescens by the pubescent foliage, diminished calyx and very large anthers, but the pods are identical. While all collectors agree that var. spinescens is a woody climber, sometimes working its way high into the canopy, Schultes and Zarucchi saw var. schultesiana in three stations as a tree 4-7 m, Steward as a treelet 3 m tall. If the difference in habit can be confirmed, the status of var. schultesiana may require reevaluation. The presence of recurving spines suggests, however, that a potentially lianalike or at least sarmentose habit of growth is a basic attribute of the species.