Erisma fuscum Ducke

Authority

Andersson, Lennart. 1998. A revision of the genus (Rubiaceae--Cinchoneae). Mem. New York Bot. Gard. 81: 1-75.

Family

Vochysiaceae

Scientific Name

Erisma fuscum Ducke

Description

Species Description - Tree ca. 25 m high; hairs where present brown; young twigs pubescent. Leaves opposite; blade coriaceous, narrowly obovate to obovate, 14-16 X 6.5 - 9 cm, glabrous above, puberulous and glabrescent below; apex obtuse, shortly acuminate, mucronate; base subcordate, folded; midvein sulcate above, prominent below; lateral veins 9-10 pairs, sulcate above, prominent below, angle with midvein 50-60°; tertiary veins percurrent, sinuous, oblique to midvein, arrangement opposite; marginal vein absent; petiole canaliculate, ca. 5 mm long; stipules unguiculate, 6- 8 mm long. Inflorescences terminal, to 25 cm long, peduncles and lateral branches pubescent; cincinni tomentose; outer bracts linear, ca. 2 mm long; inner bracts absent; pedicel to 1 mm long; buds 6-7 mm long; spurred calyx-lobe ca. 6 X 7 mm, spur uncinate-incurved, ca. 3 mm long; other calyx-lobes 2- 4 mm long; petal purple, ca. 13 X 13 mm; stamen ca. 6 mm long; style ca. 6 mm long, pilose at the base. Fruits winged, puberulous, glabrescent, to 8.5 cm long; major wing elliptic, ca. 6.5 X 3 cm; second major wing widely elliptic, ca. 2 X 1.5 cm.

Discussion

Erisma fuscum is characterized by its obovate, eucamptodromous leaves with a subcordate, folded base, and short petioles; its inflorescences covered by dark-brown hairs; its uncinate-incurved spur, and its purple flowers. It is very similar to E. uncinatum. having in common with this species unusual characters within the genus such as the eucamptodromous leaves, the uncinate-incurved spur, and the purple flowers. If it were not for the dark-brown pubescence and subcordate leaves of E. fuscum, in contrast to the orayish hairs and acute leaves of E. uncinatum, the two names could represent the same taxon. Erisma fuscum is known from only two collections, whereas E. uncinatum is the most commonly collected species of the genus. In the numerous collections studied of the latter species, the color of the inflorescences and the leaf bases are consistent. It is likely that E. fuscum is an extremely rare species. Only a single tree was seen by Ducke, who first collected and described the species (Ducke, 1925). The only other known collection is from Humaita, in the Brazilian Amazon. This area as well as the type locality near Belem, in the state of Para, represent some of the most extensively collected sites in the Brazilian Amazon. However, recent col¬lections of this species have not been made.

Distribution

Known only from two collections from nonflooded forests: the type locality in eastern Brazilian Amazonia and a second collection from central Brazilian Amazonia. It probably flowers from October to February and fruits in March.

Brazil South America|