1953] 



REVISION OF MAC R OL OB IUM 



279 



upper part of the Amazon Basin. It may be safely assumed that the range of the 

 species is the length of the basin and simply has not been collected at stations 

 intermediate between the two geographic extremes. 



Macrolobium brevense appears to be a phylogenetic node from which at least 

 two divergent lines have originated. It apparently occupies an intermediate posi- 

 tion between these two lines and M. gracile. It is most nearly allied to variety 

 machadoense of the latter species, and of the species in the two related lines of 

 relationship, it is undoubtedly most nearly related to M, huberianum. From M. 

 gracile var. machadoense , M. brevense may be most readily separated by the shape 

 of the leaf blades and the pubescence of the inflorescence. It is amply distinct 

 from M. huberianum by the glabrous bracteoles, longer pedicels, and persistent 

 stipules of the latter species. 



5. Macrolobium huberianum Ducke, Arch. Jard. Bot. Rio de Janeiro 1: 26. 1915. 

 Figure 3t 



Tall shrub or small tree 4-6 m. tall, 4-10 cm. in diameter, the branchlets pu- 

 beruious and piiosulose. Stipules 3.5-10 mm. long, 0.5—1.5 mm. wide, persistent, 

 subulate, linear, elliptic, or lanceolate, acute or acuminate, glabrous within, pu- 

 berulous externally, ciliolate. Petioles 2-4 mm. long, puberulous or piiosulose. 

 Leaf blades oblong or lanceolate-oblong, 10-23"jugate, the pairs of leaflets 3-7 

 mm. apart; rachis 4.5-9.5 cm. long, puberulous above, sometimes uncinately so, 

 the wings glabrous beneath but the axis puberulous or piiosulose. Leaflets 7-21 

 mm. long, 2.5-7 mm. wide, oblong, the base inequilateral, the upper side subcor- 

 date to cordate, the lower side acute to obtuse, the apex rotund, entire or very 

 slightly refuse, minutely apiculate; upper surface glabrous or more or less pu- 

 berulous on the costa, the hairs often uncinate, beneath appressed-pilosulose on 

 the costa, rarely also on the blade; costa slightly impressed or plane on the upper 

 surface, salient beneath, the venules obscure to subprominulous. Inflorescences 

 3-11 cm. long, the axis glabrous or piiosulose, the peduncles 2-6 mm. long; bracts 

 3.5-5.5 mm. long, 1-1.5 mm. wide, lanceolate, acuminate, glabrous except for the 

 sparsely ciliolate margins; pedicels 3.5-8 mm. long, glabrous or puberulous; brac- 

 teoles 6-10 mm. long, 3-5.5 mm. wide, elliptic, glabrous. Hypanthium 2-2.5 mm. 

 long, glabrous or sparingly piiosulose basally, sessile or with a stipe 0.5 mm. 

 long. Sepals five, 2-6 mm. long, 1-2.5 mm. wide, glabrous or apically ciliate, ob- 

 long, oblong-elliptic, lanceolate or linear-lanceolate. Petal blade 4.5-6.5 mm. 

 long, 4.5-8 mm. wide, orbicular to transversely oval, the claw 5-7 mm. long, au- 

 riculate basally, villosulose externally at the base, ciliolate on the claw, villosu- 

 lose within on the claw and on the costa of the blade. Filaments 20-30 mm. long, 

 the lower part villosulose. Stigma capitellate. Style 18-23.5 mm. long, sparsely 

 piiosulose at the base. Ovary 2.5-3.5 mm. long, 1-1.5 mm. wide, linear to oblance- 

 olate, glabrous or with a few hairs on the abaxial suture or piiosulose marginally, 

 3-5-ovulate, gynophore 2.5-5.5 mm. long, glabrous to piiosulose, inserted at the 

 apex of the adaxial wall of the hypanthium. Fruit (immature) 6-7 cm. long, 2-3.5 

 cm. wide, oblong to falcate, glabrous, the carpophores 8-10 mm. long, glabrous to 

 sparsely piiosulose, the seeds 1-2 per fruit. 



Key to the Varieties of Macrolobium huberianum 



1. Stipules 7.5-10 mm. long; leaves lanceolate-oblong; inflorescence axis piiosulose, pedi- 

 cels short-pilosulose or puberulous; sepals 5-6 mm. long, 1.5-2.5 mm. wide; ovary mar- 

 ginally piiosulose, lateral surfaces glabrous 5a. var. pubirachis . 



1. Stipules 3.5-4 mm. long; leaves oblong; inflorescence axis and pedicels glabrous; se- 

 pals 2-4.5 mm. long, 1-1.5 mm. wide; ovary subglabrous with few hairs on the abaxial 

 margin 5b. var. huberianum. 



