288 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [Vol. 8, No. 4 



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1. Ovary pubescent only on margins; bracts and bracteoles shorter; hypanthiurn glabrous; 

 leaves 10-16-jugate, rachis sparsely puberulous on axis and wing margins; leaflets 

 truncate and obtusely emarginate at apex lib. var. parviflorum. 



11a. Macrolobium flexuosum var. flexuosum. Figure 5a. 



Vouapa flexuosa (Spruce ex Benth.) Taub. Bot. Centralbl. 47: 393. 1891. 

 Vuapa flexuosa (Spruce ex Benth.) Kuntze, Rev. Gen. 1: 213. 1891. 



Tree with flexuose branches, 5 rn. tall, the branchlets pilose. Leaf blades ob- 

 long-elliptic, 10-1 1-jugate, the pairs of leaflets 10-16 mm. apart; rachis 11-14 

 cm. long, pilosulose. Leaflet base obtuse on the upper side, acute on the lower 

 side, the apex rotund and acutely emarginate, the costa impressed above, the ven- 

 ules obscure on the under surface. Inflorescences 3.5-4.5 cm. long; bracts 3 mm. 

 long, 1.5 mm. wide, puberulous on the outer surface; bracteoles 6.5 mm. long, 3-5 

 mm. wide, appressed-puberulous on the outer surface. Hypanthiurn 2 mm. long, 

 sparsely pilosulose. Sepals with the adaxial pair united at the base. Petal blade 

 about 4 mm. in diameter, orbicular, the claw 7-7.5 mm. long. Filaments about 15 

 mm. long. Ovary pilose marginally, puberulous on the lateral surfaces, 4-ovulate. 



Type Collection: R. Spruce 2593, "Falls of Panure," Rio Vaupes, Amazonas, 

 Brazil, Sept. 1852 (HOLOTYPE K, isotypes G, GH, NY, P, W). Known only by the 

 type collection. 



lib. Macrolobium flexuosum var. parviflorum (Ducke) Cowan, comb. nov. Figure 5a. 

 Macrolobium parviflorum Ducke, Bol. Tec. Inst. Agron. Norte [Belem] 2: 11. 1944. 



Small tree with puberulous branchlets. Leaf blades broadly elliptic, 10-16-ju- 

 gate, the pairs of leaflets 9-20 mm. apart; rachis 12-21.5 cm. long, sparsely pu- 

 berulous on the axis and wing margins. Leaflet base subcordate on the upper side, 

 subobtuse on the lower side, the apex truncate and obtusely emarginate, the costa 

 subsalient on the upper surface, the venules prominent. Inflorescences 3.5-6.5 

 cm. long; bracts 1.5 mm. long, 1.5 mm. wide, short-pilosulose on the outer sur- 

 face; bracteoles 5 nmi. long, 3 mm. wide, short-pilosulose externally. Hypanthiurn 

 1.5 mm. long, glabrous. Sepals free. Petal blade 3.5 mm. diameter, the claw 4 mm. 

 long. Ovary pilosulose marginally, the lateral surfaces glabrous, 2-ovulate. 



Type Collection: A. Ducke 1418 (H.J.B.R. 50739), "Cachoeira Grande, Ma- 

 naos," Amazonas, Brazil, Oct. 1943 (HOLOTYPE RB, isotypes A, F, IAN, NY, 

 US). Known only by the type collection. 



Macrolobium flexuosum appears to be near the terminus of one of the side- 

 lines of relationship which has M. brevense at its base. Its closest relatives are 

 M, venulosum and M. furcatum. It may be separated from the former by the type of 

 pubescence on the ovary, pubescence of the bracteoles, and the number of sepals. 

 From Ak furcatum it differs by its pubescent inner surface of the bracteoles and 

 by its pubescent filaments. Var. parviflorum may be further distinguished from M. 

 furcatum by the leaf outline, the length of the leaves and the size and pubescence 

 of the bracts. 



The most important differences separating the two varieties of this species 

 are the distribution of the pubescence on the ovary, the shape of the leaflet api- 

 ces, and the size of the bracts and bracteoles. 



It is an unusual circumstance that Ducke failed to relate his M. parviflorum to 

 M. flexuosum, for he rarely has been at fault in his opinions regarding the rela- 

 tionships of his new species' in this genus. The proximity of relationship is un- 

 mistakable but the differences are not of specific stature. 



12. Macrolobium furcatum Ducke, Bol. Tec. Inst. Agron. Norte [Belem] 2: 12. 1944. 

 Figure 5a. 



