STANDLEY — TREES AND SHRUBS OF MEXICO. 1259 



Leaves pubescent beneath. 



Leaves mostly less than 2 cm. long__53. S. micropliylla. 

 Leaves usually more than 2 cm. long. 



Corolla 3.2 to 3.5 cm. long 54. S. schafEneri. 



Corolla 2.5 to 2.7 cm long. 

 Leaves thin, hardly rugose, subacuminate. 



55. S. lemraoni. 

 Leaves rugose, usually rounded at apex. 



56. S. neurepia. 

 (iG. Leaves larger, all except the smallest more than 4 cm. long. 



Ijeaves glabrous beneath or nearly so 

 Calyx herbaceous, the tube becoming corrugated, the lobes sub- 

 equal , 57. S. pringlei. 



(>alyx less herbaceous, the tube not corrugated, the lobes un- 

 equal. 



Leaves cuneate or obtuse at base 58. S. involucrata. 



Leaves mostly cordate at base 59. S. pulchella. 



liCaves pubescent beneath. 



Corolla 2.5 to 2.7 cm. long 60. S. adenophora. 



Corolla 4 to 6 cm. long 

 Leaves densely white-tomentose beneath, finely crenate-ser- 



rate; calyx glandular-puberulent 61. S. fulgens. 



Leaves pilose beneath on the nerves, coarsely creuate ; calyx 

 not at all or very minutely glandular-puberulent. 



62. S. orizabensis. 

 FF. Corolla not ventricose, the tube straight or curved. 

 Leaves cuneate or narrowed at base. 

 Leaves pubescent beneath ; corolla rose-purple. 

 Corolla 1.5 to 1.8 cm. long. 



Leaves ovate or oblong-ovate 63. S. chiapensis. 



Leaves oblong-lanceolate 64. S. antennifera. 



Corolla 2.5 to 4 cm. long 65. S. curviflora. 



Leaves glabrous beneath ; corolla red 66. S. miniata. 



Leaves rounded or cordate at base. 

 Leaves cordate at base. 



Corolla purple or pink 67, S. aristulata. 



Corolla scarlet. 



Calyx in anthesis 1 cm. long 68. S. cyclophylla. 



Calyx 1.7 to 2 cm. long 69. S. incana. 



Leaves rounded or rounded-trimcate at base, not definitely cor- 

 date. 



Leaves lanceolate, 10 to 15 cm. long 70. S. perlonga. 



Leaves ovate or ovate-lanceolate, shorter. 

 G. Corolla purple or flesh-colored. 



H. Leaves glabrous or minutely puberulent beneath. 



Branches canescent-velutinous ; flower clusters 2-flow- 



ered 71. S. graciliflora. 



Branches sliglitly pilose, puberulent, or glabrous; flower 

 clusters several or many-flowered. 

 Glands (2) usually present at base of petiole; corolla 



2 to 2.7 cm. long 72. S. purpurea. 



Glands absent ; corolla 2.5 to 4 cm. long__73. S. littae. 



