1953] 



REVISION OF MACROLOBIUM 



325 



arated flowers are also distinctive. These characters serve to differentiate it from 

 its relatives M. palustre and M. savannarum. 



38. Macrolobium stenopetalum Arashoff, Bull. Torrey Club 75: 389. 1948. Figure 11. 

 Shrub 1.5-3 m. tall to small tree 10 m. tall, the branchlets and leaves gla- 

 brous. Petioles 3-6 mm. long, canaliculate. Leaflets 4-10 cm. long, 1.5-2.5 cm. 

 wide, inequilateral, strongly falcate, lanceolate, the base inequilateral, acute, 

 the apex acute to acuminate, punctate on the lower surface; costa plane to im- 

 pressed on the upper surface, salient beneath, the venules prominulous to promi- 

 nent. Inflorescences 3"5.5 cm. long, glabrous, the peduncles 5-6.5 nim. long; 

 bracts 1 mm. long and wide, persistent, triangular, acute, ciliolate; pedicels 5" 

 8.5 mm. long; bracteoles 8-13.5 mm. long, 3"5 mm. wide, oblong to lanceolate, 

 apiculate to acuminate, glabrous. Hypanthium 3-4 mm. long, sessile or with a 

 stipe to 0.5 mm. long, glabrous. Sepals four, 6-9.5 mm. long, 1.5-4 mm. wide, ob- 

 long, oblong-lanceolate, or lanceolate, acute, glabrous except for the ciliolate 

 apices. Petal 7-12.5 mm. long, 2-2.5 mm. wide near the apex, spatulate, pilosu- 

 lose externally and ciliolate at the base, villose within on the lower portion, the 

 claw not distinct. Filaments 18.5-22.5 mm. long, villose toward the base. Stigma 

 capitellate. Style 15-20 mm. long, glabrous to sparsely puberulous basally. Ovary 

 3 mm. long, 1.5 mm. wide, oblong, glabrous to sparingly puberulous on the mar- 

 gins, the lateral surfaces glabrous, 2-ovulate; gynophore 3-5 mm. long, glabrous 

 to sparsely and minutely puberulous, inserted at the margin of the adaxial hypan- 

 thial wall. Fruit 10 cm. long, 4 cm. wide, oblong, the carpophores about 13 mm. 

 long, sparsely and minutely puberulous basally. Seed 2 cm. in diameter, suborbic- 

 ular, flat, the membranous testa sparsely venulose. 



Type Collection: B. Maguire 24792> "Savanna No. IV, Tafelberg," Surinam, 

 Sept. 1944 (HOLOTYPE NY, isotypes F, U, US). 



Additional Specimens: Savanna No. II, Tafelberg, Surinam, Aug. 1944, Maguire 24232 

 (F, MO, NY, U, US); Savanna No. IV, Surinam, Aug. 1944, Maguire 24375 (F, NY, U, US). 



This species exhibits, perhaps, the greatest affinity with M. pendulum but 

 even this relationship is rather remote. It differs from the latter in the shape of 

 its leaflets, its caducous stipules, its very different petal form, and the length of 

 its hypanthium, which may be as much as twice as long. The lack of a well-delim- 

 ited claw to the petal blade is particularly striking and especially interesting be- 

 cause its form approaches that of sect. Stenosolen. 



39. Macrolobium stenosiphon Harms, Repert. Nov. Sp. 3:51. 1906. Figure 12. 

 Pseudovouapa stenosiphon (Harms) Britton & Killip, Ann. N. Y. Acad. 35: 166. 1936. 

 Tree 10-15 m. tall, 6 dm. in diameter, the branchlets glabrous. Stipules 17-25 



mm. long, 3-9 mm. wide, foliaceous, persistent through one season, falcate-ellip- 

 tic, acuminate, minutely ciliolate, otherwise glabrous. Leaves oblong, 20-30- 

 jugate, the pairs (4-)5-9(-12) mm. apart. Petioles (7-)10(-15) mm. long, canalicu- 

 late, uncinate-puberulous in the canal; rachis (ll-)18(-24.5) cm. long, uncinate- 

 puberulous or puberulous on the upper surface, glabrous beneath. Leaflets 20-30 

 mm. long, 3-10 mm. wide, lanceolate, each leaflet somewhat arcuate toward the 

 leaf apex, acuminate or infrequently acute, mucronate, the base inequilateral, the 

 upper side rounded and obtuse to subcordate, the lower side acute; margin densely 

 appressed-sericeous in a narrow band on the upper surface; costa plane to salient, 

 the venules closely parallel, prominulous. Inflorescences 5-8 cm. long, ramiflor- 

 ous, glabrous, sessile; pedicels 4-7 mm. long, glabrous; bracteoles 15.5-20 mm. 

 long, 6-7.5 mm. wide, elliptic, acute to acuminate, glabrous on the outer surface, 

 more or less puberulous within. Hypanthium 18-24 mm. long, on a stipe 1.5-2.5 

 mm. long, glabrous, gibbous at the base on the abaxial side, widening toward the 



