1953] 



REVISION OF MACROL OBIUM 



277 



the latter has a strongly lanceolate leaf outline. Both vars. machadoense and con- 

 fertum have inflorescences which are longer than those of the other two varieties 

 and similar in length to those of M. brevense. There are a number of other more 

 distant relatives of the species under discussion, which appear to have diverged 

 from the main multijugate line of relationship and which are related to M. gracile 

 through M. brevense. 



There are four moderately well-marked varieties comprising the species. Var. 

 debile and the typical variety are at once distinguishable from the others by their 

 very short, insignificant, few-flowered inflorescences. Var. debile is separable 

 from the other one by the leaflet apices and the proportions and numbers of the 

 leaflets. The characters separating the other two varieties from each other are of 

 the same nature. The leaflets of var. confertum are narrower in proportion to their 

 length than in the other variety; the leaflet costa is plane to impressed on the 

 upper surface, as opposed to strongly salient; the leaflet apices are rotund, en- 

 tire to retuse and are distinctly narrower than their bases, in contrast to the trun- 

 cate, emarginate apices of the oblong leaflets of its relative; and the leaves are 

 oblong-lanceolate, as opposed to the lanceolate ones of var. machadoense. Also, 

 the fruit of the latter is much longer than that of its relative. 



3. Macrolobium machaerioides Killip & Macbr. Field Mus. Publ. Bot. 13(3): 139- 

 1943. Figure 3. 



Small tree 2-12 m. tall, the branchlets sparingly pilosulose, sometimes also 

 densely uncinate-puberulous. Stipules 5.5 mm. long, 0.5 mm. wide, subulate-linear, 

 ciliolate. Petioles 2.5-3.5 mm. long, canaliculate, pilosulose. Leaf blades lan- 

 ceolate-oblong, 13"21-jugate, the pairs of leaflets 3.5*8 mm. apart; rachis 6.5- 

 14.5 cm. long, above with numerous uncinate hairs on the wing margins and on the 

 axis, below more or less pilosulose. Leaflets 5-25 mm. long, 2-9 mm. wide, ob- 

 long, the base inequilateral, the upper side strongly angular-auriculate, the apex 

 strongly emarginate, the upper surface uncinate-puberulous on the costa, other- 

 wise glabrous, beneath strongly pruinose and glabrous or pilose on and along the 

 costa, the latter plane to impressed above, salient beneath, the venules obscure. 

 Inflorescences 1.5*3 cm. long, the axis minutely puberulous, the peduncles 1-2 

 mm. long; bracts 1.5*2 mm. long, 1 mm. wide, triangular, acute, ciliolate, glab- 

 rous or sparsely puberulous within at the base, puberulous externally; pedicels 

 1-2 mm. long, puberulous; bracteoles 4-5 mm. long, 2-2.5 mm. wide, oblong, ex- 

 ternally short-pilosulose and puberulous, within villose. Hypanthium 1 mm. long, 

 sessile, glabrous. Sepals five, 1.5-2.5 mm. long, 1-1.5 mm. wide, the adaxial 

 pair triangular to triangular-lanceolate, sometimes partly united, the others oblong 

 to lanceolate, acute or obtuse, glabrous. Petal blade 3*4 mm. long, 4.5*5 mm. 

 wide, oval transversely, the claw 4 mm. long, more or less auriculate basally, 

 villosulose on the claw externally and sometimes upon the back of the blade, vil- 

 losulose within on the claw and up to the center of the blade, ciliolate at the 

 base of the claw. Filaments 13-16 mm. long, villose throughout most of length. 

 Stigma capitellate. Style 15 mm. long, villosulose basally. Ovary 1.5 mm. long, 1 

 mm. wide, oval, villo.se marginally, the lateral surfaces glabrous, 2-ovulate, the 

 gynophore 2-2.5 mm. long, villose, inserted at the base of the hypanthium. Fruit 

 unknown. 



Type Collection: G. Klug 547, "Mishuyacu, near Iquitos," 100 m., Dept. Lo- 

 reto, Peru, Oct.-Nov. 1929 (HOLOTYPE US, isotypes F-frag., NY). 



Additional Specimens: Maranon River from Iquitos to the mouth of the Rio Santiago at 

 Pongo de Manseriche, ca. 77° 30'West, Peru, 1924, Tessmann 4157 (G, NY). 



There can be little doubt of the relationship of this species to the M. gracile 

 complex. As was mentioned above, there are a number of species which are re- 



