372 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM; 



Pinnae 4 to 9 (rarely 3) pairs; leaflets usually puberulent, slightly 



or not at all viscid 35. A, constricta. 



Pinnae 1 or 2 (rarely 3) pairs; leaflets glabrous, very viscid. 



36. A. vernicosa. 

 Fruit turgid, tardily or not at all dehiscent; bracts borne at the summit 

 of the peduncle. 

 Pinnae 2 to 8 pairs. 



Fruit glabrous, 5 to 7.5 cm. long 37. A. farnesiana. 



Fruit pubescent, 7.5 to 10 cm. long 38. A. tortuosa. 



Pinnae 10 to 60 pairs. 



Fruit 2 to 2.5 cm. wide 39. A. pennatula. 



Fruit 0.7 to 1 cm. vpide 1. A. cochliacantha. 



Stipules not spinose, the spines infrastipular. 

 C. Leaflets large, more than 5 mm. wide, usually 1 to 2.5 cm. 



Leaflets one pair, thick-coriaceous 40. A. crassifolia. 



Leaflets 2 to many pairs, usually thin. 



Leaflets 2 or 3 pairs 41. A. rosei. 



Leaflets 4 to luany pairs. 



Stems densely setose-pilose 42. A. crinita. 



Stems glabrous. 

 Costa of the leaflets strongly excentric ; fruit 3 cm. wide ; plants 



armed with short spines 43, A. anisophylla. 



Costa of the leaflets nearly central ; fruit about 1.2 cm. wide ; 

 plants luiarmed. 

 Leaflets oblong or oval-oblong, chartaceous, the venation not 



prominent on the upper surface 52. A. penicillata. 



Leaflets broadly oval or suborbicular, nearly as broad as long, 

 coriaceous, the venation prominent on the upper surface. 



53. A. tequilana. 

 CC. Leaflets small, less than 5 mm. wide. 

 D. Petioles without glands ; flowers pedicellate ; plants unarmed. 



E. Stems hirsute or pilose with long or with short and dense, spread- 

 ing hairs. 

 Margins of the leaflets revolute ; leaflets usually pubescent on both 



surfaces with short curved hairs 44. A. polypodioides. 



Margins of the leaflets plane ; leaflets glabrous on the faces or pilose 

 with short straight hairs. 

 Pinnae 2 to 5 pairs ; leaflets 10 to 13 pairs. Stems hirsute. 



45. A, leucothrix. 

 Pinnae usually 5 to 10 pairs or more ; leaflets numerous. 



Venation of the lower surface of the leaflets not elevated. 



Leaflets glabrous beneath 46. A. villosa. 



Venation of tlie lower surface of the leaflets elevated. 

 Leaflets glabrous beneath, ciliate; fruit hirsute; stems 



sparsely hirsute 47. A. filicioides. 



Leaflets pilose beneath ; fruit glabrous or nearly so ; stems 



densely short-pilose 48. A. elegans. 



EE. Stems glabrous or puberulent, the pubescence of short, appressed 

 or incurved hairs. 

 Leaflets 1.5 mm. wide or narrower, oblong-linear or narrowly ob- 

 long, the venation not reticulate, although sometimes prominu- 

 lous. 

 Venation of the lower surface of the leaflets elevated. 



48. A. elegans. 



