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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [Vol. 8, No. 4 



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37. Inflorescence densely puberulous, the hairs usually ribbon-like; costa of leaflets sul- 

 cate on upper surface, venules prominent, petioles glabrous; lateral surfaces of ovary 

 and fruit papillate-puberulous 27. M. bifolium. 



37. Inflorescence minutely puberulous, the hairs terete; costa of leaflets not sulcate, the 

 venules subobscure, petioles minutely puberulous; lateral surfaces of ovary and fruit 

 not papillate-puberulous 38. 



38. Petioles 18-25 mm. long; leaflets 20-30 cm. long; sepals 6-6.5 mm. long 



2 5. M. unijugum. 



38. Petioles 4-13 mm. long; leaflets 8-17 cm. long; sepals 1-4 mm. long 39. 



39. Costa of leaflet minutely puberulous on upper surface and strongly salient; petioles 

 4-6 mm. long; sepals 5, lanceolate, acute 33. M. suaveolens . 



39. Costa glabrous, plane; petioles 8-13 mm. long; sepals 4, oblong or oval, obtuse 



32. M. ample xans . 



40. Leaflets broadly rotund-auriculate on lower side of base; petioles 10-16 mm. long; 



sepals 4.5-5 mm. long, oblong; petal blade 5.5 mm. long, 8 mm. wide 



31. M. duckeanum. 



40. Leaflets cuneate at base; petioles 4-5 mm. long; sepals 1.5-3.5 mm. long, lanceolate; 

 petal blade 3-4.5 mm. long, 3.5-4.5 mm. wide 33. M. suaveolens . 



41. Inflorescence densely puberulous to pilosulose, the bracts about 5 mm. long, 3 mm. 

 wide, never triangular, the bracteoles strigulose within, densely puberulous to pilosu- 

 lose externally; ovary pilosulose marginally, otherwise glabrous 



29. M. angusti folium. 



41. Inflorescence glabrous or minutely puberulous, the bracts triangular, 1-1.5 mm. long 

 and wide, the bracteoles glabrous, or minutely puberulous externally; ovary minutely 

 puberulous marginally, otherwise glabrous 42. 



42. Inflorescence glabrous; petal about as long as bracteoles, more or less spatulate, 

 without a definite claw; bracteoles oblong to lanceolate, 8-13.5 mm. long; hypanthium 

 3-4 mm. long 38. M. stenopetalum. 



42. Inflorescence minutely puberulous; petal longer than bracteoles, orbicular to trans- 

 versely oval, with well-developed claw; bracteoles oval, elliptic or oblong, 5-6.5 mm. 

 long; hypanthium 1—2 mm. long 33. M. suaveolens . 



43. Sepals five, free, or the adaxial pair more or less united 44. 



43. Sepals four, free 46. 



44. Leaflets equilateral, oval, lanceolate or ovate, not at all arcuate, the petiolules 3-5 



mm. long, terete or plane on upper surface; inflorescence glabrous or pilosulose 



22. M. arenarium. 



44. Leaflets inequilateral, oval-elliptic to elliptic, falcate or arcuate, epetiolulate; in- 

 florescence axis minutely puberulous 45. 



45. Leaflets epunctate beneath, acute; bracts at base of inflorescence persistent, closely 

 imbricate, sterile; ovary and gynophore glabrous 34. M. parvifolium. 



45. Leaflets punctate beneath, acuminate; bracts caducous; gynophore pilosulose on ad- 

 axial surface 33. M. suaveolens. 



46. Hypanthium 2.5-3.5 mm. long on stipe 2-4 mm. long; bracteoles apically rounded, apic- 

 ulate or cuspidate, carnose, often early caducous; leaflets on petiolules 2-10 mm. 

 long; petioles flattened dorso-ventrally 47. 



46. Hypanthium 1-2 mm. long, sessile or with stipe 1 mm. long; bracteoles acute to acu- 

 minate, persistent; leaflets sessile, petioles terete 48. 



47. Leaflets strongly rounded on lower side of base, often punctate beneath, falcate, apex 

 acute to acuminate; sepals 4-7.5 mm. long; petal 4-5.5 mm. wide, more or less erect; 

 bracteoles 3.5-8 mm. long, 2-3.5 mm. wide 24. M. punctatum. 



47. Leaflets not rounded basally, epunctate, moderately arcuate, apex rounded-obtuse; 

 sepals 9.5-11 mm. long; petal 7-8 mm. wide, strongly recurved; bracteoles 10.5 mm. 

 long, 5 mm. wide 23. M. canaliculatum. 



48. Stipules and rachis rudiment persistent; hypanthium strongly zygomorphic; leaflets 



often punctate. Belem and Amazon Delta region to southern Amazonas 



37. M. pendulum. 



48. Stipules and rachis rudiment caducous; hypanthium symmetric to asymmetric; leaflets 

 epunctate. Eastern Peru, upper Rio Negro and southwestern Venezuela 49. 



49. Filaments glabrous; petioles 1.5-4 mm. long; leaflets 1.5-5.5 cm. long, 1-2.5 cm. 

 wide, lower side of base rounded 36. M. savannarum. 



49. Filaments pubescent toward base; petioles 7-18 mm. long; leaflets larger, base cune- 

 ate 50. 



50. Leaves always unijugate, the leaflets 11.5-17 cm. long, narrowly elliptic, the petioles 

 7—9 mm. long; inflorescence axis microscopically puberulous, the pedicels 4-5 mm. 



