STANDLEY TREES AND SHRUBS OF MEXICO. 373 



Venation of the lower surface of the leaflets not elevated. 

 Pinnae usually 3 to 6 pairs ; leaflets commonly 10 to 15 pairs ; 



leaves rarely over 5 cm. long 49. A. cuspidata. 



Pinnae usually 6 to 10 or more pairs ; leaflets numerous ; leaves 



usually 8 to 10 cm. long or larger 50. A. angustissima. 



Leaflets 2 to 7 mm. wide, oval or broadly oblong, the venation 

 reticulate, prominent. 



Pinnae 8 to 11 pairs 51. A. laevis. 



Pinnae 3 to 5 pairs. 



Leaflets oval-oblong, about twice as long as broad. 



52. A. penicillata. 

 Leaflets quadrangular-orbicular, nearly as broad as long. 



53. A. tequilana. 

 1 >r>. Petioles with glands ; flowers sessile or nearly so ; plants usually 

 armed with spines. 

 Pinnae 6 to many pairs in all or most of the leaves. 



Leaflets linear or oblong-linear, 1 mm. wide or narrower. 

 Fruit long-stipitate, glabrous or nearly so, very thin. 



54. A. paniculata. 

 Fruit sessile, densely velvety-puberulent, thick. 



55. A. berlandieri. 

 Leaflets oblong, or narrowly oblong, more than 1 mm. wide. 

 Costa of the leaflets close to the upper margin. 



56. A. g-lomerosa. 



Costa remote from the margin. 



Leaflets thick, densely puberulent beneath ; fruit subsessile, 



densely puberulent, the valves thick__57. A. subangulata. 



Leaflets thin, glabrous or nearly so; fruit stipitate, glabrate, 



the valves thin 58. A. riparia. 



Pinnae 1 to 4 pairs. 



Rachis of the leaves or pinnae armed with spines. 



Leaflets glabrous, 4 or 5 pairs 59. A. palmeri. 



Leaflets pubescent, 6 to 14 pairs. 



Leaflets 6 to 10 pairs; valves of the fruit thin. 



60. A. malacophylla. 

 Leaflets 10 to 14 pairs ; valves of the fruit thick. 



61. A. purpusii. 

 Rachis of the leaves and pinnae unarmed. 



Leaflets 1..5 mm. wide or narrower 62. A. occidentalis. 



Leaflets 2.5 to 5 mm. wide. 



Leaflets oval-oblong, bright green 63. A. micrantha. 



Leaflets cuneate-oblong, glaucescent 64. A. roemeriana. 



1. Acacia cochliacantha Humb. & Bonpl. ; Willd. Sp. PI. 4: 1081. 1806. 

 llimosa campeachiana Mill. Gard. Diet. ed. 8. Mimosa no. 20. 17G8. 

 Chihuahua to Ba.ia California, Puebla, and Chiapas. South America; type 

 from Guayaquil, Ecuadoi*. 



Shrub or small tree, 1.5 to 4.5 meters high: spines, especially those on sterile 

 branches, very large, 1.5 to 5 cm. long, boat-shaped, brown or gray, those on 

 fertile branches mostly subulate; leaflets very numerous, 2 to 3 mm. long, 

 linear; flowers yellow; fruit compressed or nearly terete, usually 9 to 10 cm. 

 long, blackish brown, tardily dehiscent or indehiscent. " Quisache corteno," 

 "quisache tepamo " (Michoacan, Guerrero); " cucharitas," " palo de cuchari- 

 tas " (Oaxaca). 



