166 American Midland Naturalist Monograph No. 4 



Leaves egg-shaped to oblong-egg-shaped, pointed or 

 tapering at tips; flower-clusters slender-stalked, 

 borne at ends of branches of the season ; east- 

 ern species 9. C. americanus. 



Leaves grayish and dingy-looking vv'ith fine gray hairs 



10. C. molissimus. 



Leaves thickish, shiny above as if varnished; evergreen; foliage often 



with a strong cinnamon-like odor; fruits sticky 



11. C. veluiinus. 



Leaves opposite, thickish, with 1 main vein; capsules with a horn at or near top of 

 each lobe. 



Generally low, spreading, or prostrate shrubs; flowers blue (sometimes white in 

 C. pinetorum). 



Leaves 1/6 to J/2 inch long, squared at tips and more or less toothed; 



fruits with slender horns on sides near top 12. C. fresnensis. 



Leaves 1/3 to 1 inch long, with stiff sharp-pointed teeth; fruits with stout 

 horn at top of each lobe. 



Leaves mostly 3-toothed at tip; found in Crater Lake, Lassen, and 



Yosemite National Parks 13. C. prosiralus. 



Leaves mostly several-toothed along the sides; found in Sequoia Na- 

 tional Park 14. C. pineiorum. 



Erect shrubs 2 to 12 feet high; leaves not toothed or only slightly so; flowers 

 white. 



Plants 4 to 12 feet high; horns of fruits attached at or near top; found in 



Sierra Nevada parks 15. C. cuncatus. 



Plants 2 to 4 feet high; hoins of fruits attached laterally; found in South- 

 west 16. C. veslitus. 



1. Chaparral Whitethorn Ceanothus (Ceanothus leucodermis 

 Greene). — Large shrub 5 to 16 feet high, often forming dense thickets; 

 branchlets whitish, rigid, some of them spine-tipped; leaves ^ to 1^ inches 

 long, oval, rounded at base, somewhat pointed at tips, thickish, smooth and 

 green above, paler below, with 3 main veins, the margins finely toothed or not 

 toothed; flowers blue or white, borne in narrow, usually unbranched clusters 

 1 to 2 inches long; capsules nearly round, about I/4 inch in diameter, smooth 

 but rather sticky. The seeds sprout readily after fire, hence it is one of the 

 first species to come into burned areas. (Syn. C. divancatus Auth., not Nutt.) 



Occurrence. — YOSEMITE, rare, 3,000 to 6,000 feel: Yosemite Valley, near post 

 office; near El Portal; Wawona. SEQUOIA, occasional, 3,500 to 6,500 feet: Switchback 

 Peak; head of Burnt Camp Creek; Cedar Creek, North Fork Kaweah ; Clough Cave. 



2. Mountain Whitethorn Ceanothus {Ceanothus cordulatus 

 Kell.). — Low, round-topped, much-branched, spreading shrub 1 to 4 feet 

 high with crooked, rigid, spine-tipped branches and whitish bark; leavci 

 smooth or very finely hairy, thickish, elliptic to roundish, ^ to 1 inch long, 

 with 3 veins from the base, the margins usually not toothed; flowers white, 

 with a sickening-sweet odor, borne in small dense clusters 1/2 to 1^2 inches 

 long; fruits about 1/6 inch in diameter, 3-lobed, with a narrow ridge down the 

 back of each lobe. The bushes sometimes form dense covers over extensive 

 areas on openly forested mountain slopes or flats, particularly in ponderosa pine 

 and white fir stands of California and southwestern Oregon. 



