STANDLEY — TREES AND SHRUBS OF MEXICO. Ill 



Leaves thick and fleshier; spine rather stout. 



Spine flat-grooved 71. A. chihuahuana. 



Spine round-grooved, sharp-edged. 



Leaves elongate; capsule about 4 em. long 72. A. parryi. 



Leaves broad ; capsule 5.5 to 7.5 cm. long. 



Leaves acute 69. A. huachucensis. 



Leaves acuminate 73. A. patonii. 



HHH. Leaves triangular or lance-oblong, ascending. 

 Leaves elongate .(fully 1 meter long). 



Perianth segments twice as long as tube 74. A. aurea. 



Perianth segments shorter than tube 75. A. promontorii. 



Leaves scarcely half as long. 



Teeth close together (5 to 10 mm. apart), small. 



Teeth friable, almost cuspless 76. A. dentiens. 



Teeth firm, with short sharp cusps 77. A. disjuncta. 



Teeth more separated, sometimes very large. 

 Spine nearly straight. 

 Spine strong and rather stout. 

 Leaf margin repand. 



Ovary flask-shaped 78. A. desertl. 



Ovary fusiform 79. A. consociata. 



Leaf margin nearly straight 80. A. pringlei. 



Spine very slender. 



Leaves roughened 81. A. cerulata. 



Leaves smooth. 



Perianth- segments 15 mm. long 82. A. carminis. 



Perianth segments 20 mm. long 83. A. sobria. 



Spine somewhat tortuous. Leaves roughened 84. A. affinis. 



HHHH. Leaves broadly lanceolate or oblanceolate. 



Teeth small, close together (10 mm.) 85. A. brandegeei. 



Teeth larger and more separated. 

 Teeth gradually tapered. 



Teeth comparatively short and straight 86. A. margaritae. 



Teeth long and often hooked 87. A. connochaetodon. 



Teeth abruptly contracted from the base. 



Spine undulate; margin repand 88, A. roseana. 



Spine and margin straight 89. A. avellanidens. 



HHHHH. Leaves oblong or ovate-oblong ; spine straight. 



Teeth long- and firm 90. A. subsimplex. 



Teeth short, detachable 91. A. nelsoni. 



AAAA. Leaves horny-margined for the upper third or more, fleshy, large. 

 Leaves broad (3 times, or rarely 4 or 5 times, as long as wide). 



Margin with few and rudimentary teeth or none 92. A. weberi. 



Margin with numerous strong teeth. 



Teeth confluent on much of the margin 93. A. latissima. 



Teeth joined by a horny margin only toward the end. 



Leaves undulate, very crenate, green 94. A. ferox. 



Leaves not very crenate if green. 



Leaves deeply gutter-shaped 96. A. compluviata. 



Leaves not gutter-like. 



Leaves scarcely twice as long as broad 95. A. m.itraefonnis. 



