STANDLEY — TREES AND SHRUBS OF MEXICO. 721 



Stipules thin and deciduous ; leaves alternate ; capsule without horns ; flowera 

 blue or white, usually racemose. 

 Leaves glabrous beneath or with a few closely appressed, straight hairs; 

 branchlets glaucous or glaucescent. 



Leaves pinnate-nerved 6. C. spinosus. 



Leaves 3-nerved 7. C. divaricatus. 



Leaves copiously pubescent beneath, usually densely so, often tomentose ; 

 branchlets never glaucous. 

 Branchlets never spinose ; petals usually blue ; flowers mostly in elongate 

 racemes. 

 Leaves 1 to 2 cm. long, densely and minutely sericeous beneath. 



8. C. tomentosus. 

 Leaves mostly 3 to 8 cm. long, coarsely tomentose beneath. 



9. C. coeruleus. 

 Branchlets spinose ; petals white ; flowers umbellate. 



Leaves entire 10. C. huichagorare. 



Leaves finely serrulate. 



Lower surface of the leaf finely white-sericeous between the nerves. 

 Leaves suborbicular, rounded at base, glabrate on the upper surface. 



11. C. pueblensis. 

 Leaves oval-obovate to cuneate-obovate, obtuse or cuneate at base, 



sericeous on the upper surface 12. C. durangoinus. 



Lower surface of the leaf tomentose, or the pubescence consisting of 

 long loose hairs, these all or chiefly confined to the nerves. 



Capsule coarsely tuberculate and cristate 13. C. ferox. 



Capsule smooth. 



Leaves sparsely or densely tomentose beneath, the hairs matted. 

 Leaves glabrous or nearly so on the upper surface, very sparsely 



tomentose beneath 14. C. depressus. 



Leaves densely pubescent on the upper surface or very tardily 



glabrate, densely tomentose beneath 15. C. endlichii. 



Leaves pilose beneath along the nerves with long straight hairs. 



16. C. buxifolius. 



1. Ceanothus verrucosus Nutt. ; Torr. & Gray, Fl. N. Amer. 1: 267. 1838. 

 Northern Baja California. Southern California ; type from San Diego. 

 Low shrub with gray or brown branches ; leaves cuneate-obovate or rounded- 



obovate, 4 to 12 mm. long, rounded or retuse at apex, entire or denticulate, 

 minutely tomentulose beneath or glabrate; flowers white. 



2. Ceanothus goldmanii Rose, Contr. U. S. Nat. Herb. 12: 284. 1909. 

 Mountains of Baja California ; tJTe from La Huerta. 



Stout shrub, 2 to 4 meters high, often forming dense thickets ; leaves cuneate- 

 obovate to suborbicular. 7 to 14 mm. long, coarsely dentate, minutely tomentu- 

 lose or glabrate beneath. 



This has been reported from Baja California as C. rigidiis Nutt. 



3. Ceanothus cuneatus (Hook.) Nutt.; Torr. & Gray, Fl. N. Amer. 1: 267. 1838. 

 Rhamnus cuneata Hook. Fl. Bor. Amer. 1: 124. 1829. 



Ceanothus suhmontamis Rose, Contr. U. S. Nat. Herb. 12: 284. 1909. 

 Baja California. California and Oregon. 



Shrub, 1 to 3 meters high, with gray branches ; leaves 6 to 15 mm. long, ob- 

 tuse or rounded at apex, nearly sessile, minutely tomentulose beneath. 

 780&— 23 14 



