REVISION OF MACROLOBIUM 



319 



The inflorescences of M. amplexans are ramiflorous and are minutely puberu- 

 lous with simple hairs, whereas those of M. bifolium are borne principally on the 

 current year's branchlets and are densely puberulous with ribbon-like hairs. Fur- 

 ther, the flowers of the latter are typically densely congested, but in A1. amplexans 

 they are distant. Also the costa of the leaflets in the latter is not sulcate on the 

 upper surface as it is in W. bifolium nor are the venules prominent on the upper 

 surface of the leaflets. 



33. Macrolobium suaveolens Spruce ex Benth. in Mart. Fl. Bras. 15(2): 219. 1870. 

 Figure 11. 



Tree to 13 m. tall, the branchlets usually glabrous, rarely pilosulose or mi- 

 nutely puberulous. Petioles glabrous or minutely puberulous, sulcate to canalicu- 

 late. Leaflets 7-14 cm. long, 3-5.5 cm. wide, arcuate to falcate, elliptic, the base 

 inequilateral, acute, the apex acute to acuminate, the extremity acute to obtuse; 

 lower surface punctate or epunctate, glabrous, upper surface glabrous or puberu- 

 lous on the costa and base; costa plane to salient, the venules obscure to promi- 

 nent. Inflorescences 2-8 cm. long, the axis minutely puberulous, the peduncles 

 1-3 mm. long; bracts 1-1.5 mm. long and wide, triangular or ovate, acute or acu- 

 minate, ciliolate, glabrous or infrequently minutely puberulous on the outer sur- 

 face; pedicels 1-4.5 mm. long, sparsely puberulous or glabrous; bracteoles 5-6.5 

 mm. long, 2.5-4 mm. wide, oblong or oval, glabrous within or sparingly pilose, 

 minutely puberulous externally, at least at the apex. Hypanthium 1-2 mm. long, on 

 a stipe to 1 mm. long or sessile, glabrous or sparsely puberulous. Sepals five, 

 free or infrequently the adaxial pair partly united, 1-4 mm. long, 0.5-1.5 mm. 

 wide, lanceolate, linear-lanceolate, oblong or elliptic, or when strongly dimorphic, 

 the adaxial pair triangular and smaller, glabrous or ciliolate near the apex. Petal 

 blade 3-7 mm. long, 3.5-7 mm. wide, orbicular to transversely oval, the claw 4-6 

 mm. long, wider at the base to definitely auriculate, pilose externally toward the 

 base, the claw more or less ciliolate, glabrous within or sparingly villose. Fila- 

 ments 15.5-21 mm. long, villose or villosulose in the basal portion. Stigma capi- 

 tellate, capitate, or peltate. Style 10-22 mm. long, glabrous or more often puberu- 

 lous basally. Ovary 1-2.5 mm. long, 1-1.5 mm. wide, oblong or oval, glabrous to 

 minutely puberulous, 2-3-ovulate; gynophore 2-3.5 mm. long, minutely puberulous 

 or pilosulose. Fruit unknown. 



Key to the Varieties of Macrolobium suaveolens 



1. Ovary glabrous, adaxial surface of gynophore pilosulose; leaflets with upper margin 

 about straight, lower margin arcuate 33e. var. suaveolens . 



1. Ovary minutely puberulous on all surfaces or only on margins with lateral surfaces gla- 



brous; bota margins of leaflets arcuate 2. 



2. Ovary puberulous on all surfaces 3. 



2. Ovary puberulous only on margins 4. 



3. Leaflets epunctate on lower surface, minute-puberulous above at base and on most of 



length of strongly salient costa, petioles densely minutely puberulous. Potaro River 

 region of central British Guiana 33a. var. pakarimense . 



3. Leaflets punctate on lower surface, glabrous, costa plane to salient on upper surface, 



petioles glabrous. Central Brazil 33b. var. rondonianum . 



4. Bracteoles more or less pilose within; petioles mostly 7-13 mm. long 



33c. var. petiolatum. 



4. Bracteoles glabrous on inner surface; petioles 3.5-6 mm. long. 33d. var. uaupesense. 



33a. Macrolobium suaveolens var. pakarimense Cowan, var. nov. Figure 11. 



Arbor 10-13 m. alta, 15 cm. diametro, ramulis minute puberulis. Petiolus 4-6 

 mm. longus, leviter sulcatus, valde minuto-puberulus. Foliola 7-9.5 cm. long'a, 3" 

 4 cm. lata, arcuata, ad apicem abrupte acuta, extremitate obtusa vel acuta, supra 

 in costa minute puberula, infra glabra, costa valde salienti supra, infra plana, 



