1953] 



REVISION OF MACROLOBIUM 



287 



mature) 7-7.5 cm. long, 2.5 cm. wide, oblong, sometimes broader toward the apex, 

 glabrous or with a few marginal hairs, the carpophores 8-1^ mm. long, puberulous. 



Type Collection: R. Spruce 3l33 y "San Carlos," Rio Negro, Amazonas, Vene- 

 zuela, Oct. 1853 (HOLOTYPE K, isotypes G, GH, NY, P, US-frag., W). 



Additional Specimens: COLOMBIA: Rio Negro, vicinity Piedra de Cocui, Vaupes, Dec. 

 1947, Schultes & Lopez 9530 (US). 



There are two sheets bearing the type collection number at Geneva, one of 

 which is a fruiting specimen. The latter may be part of a second Spruce collec- 

 tion, for the leaflets are smaller and pilosulose on the lower surface. Also, it has 

 shorter petioles and rachises. It is certain that Bentham did not study this ma- 

 terial because he specifically states in his original description of the species 

 that he had no fruit available for his examination. 



This species shows the greatest affinity with M. flexuosum, particularly with 

 var. parviflorum of that species. It differs from that variety by having smaller 

 leaflets which are usually glabrous, closer to each other, and the ovary is mar- 

 ginally puberulous instead of pilosulose. From M. froesii, to which it also bears 

 some relationship, it may be separated by the shape of the leaflet apex, the length 

 of the pedicels, and the pubescence of the bracteoles and filaments. 



11. Macrolobium flexuosum Spruce ex Benth. in Mart. Fl. Bras. 15(2): 223. 1870. 

 Figure 5a. 



Tree 7-10 m. tall, the branchlets puberulous or pilose. Petioles 6-9 mm. long, 

 sulcate lightly or canaliculate on the upper surface, pilosulose or puberulous. 

 Leaf blades oblong-elliptic or broadly elliptic, 10-l6-jugate, the pairs of leaflets 

 9-20 mm. apart; rachis 11-21.5 cm. long, pilosulose, or sparsely puberulous on 

 the axis and the wing margins. Leaflets 11-45 mm. long, 5-15 mm. wide, oblong, 

 the base inequilateral, the upper side obtuse to subcordate, the lower side acute 

 to subobtuse, the apex rotund or truncate, obtusely or acutely emarginate; upper 

 surface lustrous, glabrous except puberulous on the costa, the hairs uncinate or 

 arcuate, beneath pilosulose, sometimes sparingly so, costa more strongly pubes- 

 cent; costa impressed or subsalient above, salient beneath, the venules numerous, 

 closely parallel, prominent on both surfaces or obscure beneath. Inflorescences 

 3.5-6.5 cm. long, rarely with a lateral branchlet, the axis puberulous, the peduncle 

 1-2 mm. long; bracts 1.5*3 mm. long, 1.5 mm. wide, early caducous, triangular- 

 ovate, ciliolate, glabrous within, puberulous or short-pilosulose externally; pedi- 

 cels 2-3.5 mm. long, puberulous; bracteoles 5-6.5 mm. long, 3-3.5 mm. wide, el- 

 liptic, cuspidate-acute, appressed-puberulous or short-pilosulose externally, vil- 

 losulose within. Hypanthium 1.5-2 mm. long, glabrous or sparsely pilosulose. Se- 

 pals five, tree or the adaxial pair slightly united at the base, the dorsal pair 2-2.5 

 mm. long, 1.5 mm. wide, triangular, the others 3~3«5 mm. long, 1.5-3 mm. wide, 

 oblong to oval or lanceolate, ciliolate apically. Petal blade 3.5 mm. long, 4 mm. 

 wide, suborbicular, pilosulose up to the center externally, glabrous or villosulose 

 sparsely within, the claw 4-7.5 mm. long, glabrous or pilosulose externally, cilio- 

 late, villosulose within. Filaments villosulose basally. Stigma simple or capitel- 

 late. Style pilosulose at the base. Ovary 1.5-2 mm. long, 1-1.5 mm. wide, linear- 

 elliptic or oblong, marginally pilosulose or villosulose, laterally pilosulose or 

 glabrous, 2-4-ovulate, the gynophore 1.5-2 mm. long, pilosulose, inserted in the 

 base of the hypanthium. Fruit unknown. 



Key to the Varieties of Macrolobium flexuosum 



1. Ovary pubescent throughout; bracts 3 mm. long; bracteoles 6.5 mm. long; hypanthium 

 sparsely pilosulose; leaves 10-1 1-jugate, rachis pilosulose; leaflets rotund and acutely 

 emarginate at apex 11a. var. flexuosum. 



