64 RHAMNACEAE 



ex Curran Proc Calif. Acad. II. 1:251. 1888.) This is distinguished from the green-leaved form of the 

 subspecies ilicifolia by the pilose or densely grayish-puberulent twigs and petioles. It occurs on the western 

 slopes of the mountains in San Diego County, extends eastward to the desert slopes of southern California and 

 Arizona and south to northern Lower California. Type locality: Santa Maria Valley, San Diego County, 

 California. 



Rhamnus crocea subsp. pirifolia (Greene) C. B. Wolf, op. cit. 45. (Rhamnus pirifolia Greene, Pittonia 

 3: 15. 1896.) Closely related to the subspecies ilicifolia from which it differs chiefly in being: more arboreal 

 and having larger leaves, which are less sharply toothed. It has been confused with Rhamnus insnliis Kell. of 

 Cedros Island, Lower California. Santa Rosa, Santa Cruz, Santa Catalina, and San Clemente Islands, California, 

 and Guadalupe Island, Lower California. Type locality: Santa Cruz Island. 



3. CEANOTHUS L. Sp. PI. 195. 1753. 



Unarmed or spinescent shrubs or rarely small trees with alternate or opposite de- 

 ciduous or evergreen leaves. Flowers white, blue, or purple, in terminal or axillary- 

 panicles or cymes. Calyx 5-lobed, the lobes petaloid and deciduous. Petals hooded, long- 

 clawed. Ovary immersed in the disk and adnate to it at the base, 3-lobed. Disk adnate to 

 the calyx. Style 3-cleft. Capsule somewhat 3-lobed, often crested or horned, separating 

 at maturity into 3 nutlets. [Name used by Theophrastus for some plant.] 



An American genus of about 60 species, most abundant in California. Type species, Ceanothus ameri- 

 canui L. 



Stipules thin and early deciduous; leaves alternate, their stomata on the lower surface never in sunken pits; 

 capsules smooth or sometimes ridged or crested on the middle of the lobes. (Section Euceanothus) 

 Ultimate branches flexible at least not rigidly divaricate and spinose. 



Leaves glandular-denticulate, serrulate or serrate (except Parryi) and evergreen (except sanguineus). 

 Leaves distinctly 3-nerved from the base, sometimes appearing 1-nerved in Parryi. 

 Branchlets terete. 



Leaves deciduous; flowers white. 1- C. sanguineus. 



Leaves evergreen. 



Leaves varnished above and strongly scented; flowers white. 



» 2. C. veluttnus. 



Leaves not varnished above; flowers blue. 



Under surface of leaves white-tomentose. 



Leaves 5 cm. long or more; flowers in an ample panicle. 



3. C. arbor eus. 



Leaves less than S cm. long; flowers in a small raceme. 



4. C. tomentosus. 



Under surface of leaves green and glabrous or sparsely pubescent. 



Leaves bright green and glabrous on both surfaces; raceme elongated. 



5. C. cyaneus. 



Leaves more or less pubescent on both surfaces; raceme short. 



6. C. oliganthus. 

 Branchlets angled and striated. 



Leaves plane, distinctly 3-nerved. 



Leaves green and glabrous between the veins beneath, the margins not revolute. 



7. C. thyrsiflorus. 



Leaves tomentulose between the veins beneath, margins narrowly revolute. 



8. C. griseus. 



Leaves often appearing l-nerved, the lateral veins obscured by the strongly revolute 

 margins. 9. C. Parryi. 



Leaves 1-nerved from the base. 



Leaves more or less revolute on the margins. 



Upper surface of leaves papillate. 10. C. papillosus. 



Upper surface of leaves not papillate, or only on the fold of the revolute margin. 



Leaves orbicular to broadly elliptic, upper surface deeply grooved over the midrib 

 and lateral veins, the margins sometimes slightly glandular. 



11. C. impressus. 



Leaves elliptic to narrowly oblong, appearing truncate due to the infolding at apex, 

 sometimes glandular-papillate along the apparent margin, the true infolded 

 margin glandular-denticulate. 12. C. dentatus. 



Leaves plane, their margins not revolute, lateral veins sometimes rather prominent. 

 Prostrate shrub; flowers few (3-8) in short racemes. 13. C. diver sif alius. 



Erect shrubs with ascending or spreading branches. 



Branches elongated, spreading; capsule prominently crested. 



14. C. Lentmontt. 



Branches erect or ascending; crests of the capsule inconspicuous. 



Capsule deeply lobed; calyx-lobes narrowly triangular, less than 2 mm. long. 



15. C. foliosus. 



Capsule shallowly lobed; calyx-lobes broadly triangular, 2 mm. long. 



16. C. austromontanus. 



Leaves entire or rarely few-toothed at the apex, plane, branchlets terete. 



Capsules 3.5-4.5 mm. broad, obscurely crested and otherwise smooth; leaves deciduous. 



Peduncles naked; leaves narrowly oblong, narrowed at base, glabrous, 1-nerved; flowers blue. 



17. C. parvifolius. 



Peduncles more or less leafy; leaves rounded to subcordate at base, 1-3-nerved; flowers white 

 or when blue the leaves pubescent. 18. C. integerrimus. 



Capsules 5-7 mm. broad, roughened with a wrinkled exocarp and crested with a roughened ridge; 

 leaves 1-nerved, evergreen. 19. C. Palmeri. 



