Monographs Details: Macrolobium multijugum var. sinuatum R.S.Cowan
Authority: Cowan, Richard S. 1953. A taxonomic revision of the genus Macrolobium (Leguminosae-Caesalpinioideae). Mem. New York Bot. Gard. 8 (1): 257-342.
Family:Caesalpiniaceae
Description:Latin Diagnosis - Petiolus 2-3.5 cm. longus, canaliculatus, glaber. Foliorum lamina 5-6-jugata, paribus 1.5-2.5 cm. separatis; rachibus 7-8 cm. longis, glabris. Foliola 4.5-8.5 cm. longa, 1-2.5 cm. lata, anguste oblonga, margine sinuato, ad basim inaequalia sed ambobus lateribus acutis, ad apicem obtusa, apiculata, glabra. Inflorescentiae 5-9 cm. longae,axe glabro, pedunculo 1-3 cm. longo; pedicellis 2-4.5 mm. longis, glabris; bracteolo 7 mm. longo, 4 mm. lato, ovato-lanceolato, glabro. Sepala 3-4 mm. longa, 0.5-1.5 mm. lata, lanceolata, glabra. Filamenta 15 mm. longa.. Stigma paulo incrassatum. Ovarium 2-2.5 mm. longum, 1.5-2 mm. latum,ovale vel ovatum, glabrum. Fructus ignotus.

Discussion:

Type Collection: R. Spruce 2440, "prope Panure ad Rio Uaupes," Brazil, Oct.-Jan. 1852-53 (HOLOTYPE GH, isotypes BM, G, K, NY, P, W).

On one of the isotypes at Kew, Spruce notes, " the Ivs being rendered narrower & their margins wavy by the puncture of insects in the bud." However, I have failed to find any suggestion of damage to any part of the specimens examined and I believe that these differences are natural, not due to insect injury as Spruce supposed.

This species is so variable in most of its characters that it is very difficult to enumerate a number of characters which will infallibly separate it from other related species. However, the punctation of the lower leaflet surface and the elongate peduncles of this species are characteristics which reliably distinguish it.

Macrolobium multijugum is rather closely related to M. molle and to M. discolor. It may be separated from the first of these by its glabrous or nearly glabrous leaflets and glabrous or minutely puberulous inflorescence axis. From M. discolor it is distinct by its glandular punctations on the lower leaflet surfaces, its elongate peduncles, and its very different fruit shape.

The two varieties involved differ only by the shape and margin of their leaflets. Whereas the margins of the broadly oblong to oblong-obovate leaflets of the typical variety are entire, the margins of the narrowly oblong ones of the other variety are distinctly sinuate.