1953] 



REVISION OF MACROLOBIUM 



297 



wide, triangular-lanceolate to lanceolate, acuminate to caudate-acuminate, glab- 

 rous. Petal blade 2.5-5.5(-7) mm. long, 4-5 mm. wide, transversely oval, the claw 

 2-4 mm. long, auriculate or merely expanded at the base, more or less pilosulose 

 on the outer surface or rarely glabrous, villosulose within, sometimes sparsely so, 

 claw ciliolate. Filaments (10-)l6-18 mm. long, villosulose in the -lower part. 

 Stigma capitellate. Style (8.5— )1 1—16.5 mm. long, villose basally. Ovary 1.5-2 mm. 

 long, 1 mm. wide, oblong, 2-ovulate, villose on all surfaces, the gynophore 1.5- 

 2.5 mm. long, villosulose, inserted on the base or up to midway on the adaxial hy- 

 panthial wall. Fruit unknown. 



LECTOTYPE: A. Ducke (H.J.B.R. No.) 23298, "Estrada do Aleixo, Manaos," 

 Amazonas, Brazil, Sept. 1929 (deposited RB, isolectotypes G, P, U, US). 



Additional Specimens: BRAZIL: Amazonas: Camanaos, Sept. 1935, Ducke 34 (A, F, 

 IAN, MO, NY, US); Camanaos, upper Rio Negro, Nov. 1929, Ducke (H.J.B.R. No.) 23299 

 (US). 



PERU: Mishuyacu, near Iquitos, Dept. Loreto, 1929-30, Klug 140, 387. 1043 (NY, US). 



The nearest relative of M. microcalyx is M. montanum, especially the typical 

 variety of the latter. The following characters of M. microcalyx serve to distin- 

 guish it from its nearest relative: (1) its sepals are strongly dimorphic in both 

 size and shape; (2) the ovary is villose on all surfaces; and (3) it usually has 

 more pairs of leaflets per leaf. 



18. Macrolobium montanum Ducke, Arch. Bot. Jard. Rio de Janeiro 4: 49. 1925. 

 Figure 7. 



Small shrub 1-1.5 m. tall or small tree 10-13 ra. tall, the branchlets glabrous, 

 or minutely puberulous but then glabrescent. Petioles 7-13 ram. long, glabrous. 

 Leaf blades 2-3-jugate, the pairs 7-17 mm. apart; rachis 8-32 mm. long, glabrous. 

 Leaflets 17-32 mm. long, 10-25 ram. wide, oval to suborbicular or oblong to obo- 

 vate, the base inequilateral, the upper side cordate, the lower rotund-obtuse or 

 acute, the apex rotund, retuse to emarginate; glabrous, or very sparsely puberu- 



FIG. 7. Geographic distribution of M. microcalyx, M. montanum, M. urupaense, M» guia- 

 nense, M. campestre, and M. arenarium. 



