466 RHAMNACEAE 



Mts., Berg fried; North Berkeley Hills, Jepson 9634; Mt. Tamalpais, Jepson 14,006; betw. Philo 

 and Greenwood, Mendocino Co., Jepson ; betw. Comptche and Low Gap, Mendocino Co., Jepson 

 2170; Ft. Bragg, TV. C. Mathews; Wcott, Humboldt Co., Jepson 16,492; Korbel, n. Humboldt 

 Co., Jepson 1928 ; Big Lagoon, Humboldt coast, Jepson 9409 ; Crescent City, Davy. 



Var. griseus Trel. Branchlcts stout ; leaf -blades roundish-ovate to elliptic, obtusish, silky 

 beneath with dense short hairs, as much as 1% inches long, the margin revolute between the low 

 teeth; panicles rather large (1^/4 inches long) but dense and compact. — Mill Creek near Posts, 

 Santa Lucia Mts., Jepson 2609; Monterey; Ft. Koss. 



Var. chandler! Jepson. Branchlets slender; leaf -blades small (10 lines long or less), puberu- 

 lent beneath; panicles subglobose, 7 to 8 lines long on peduncles 2 to 3% inches long; flowers 

 pale blue. — Pajaro Hills, Monterey Co. 



Kefs. — Ceaxothus thyrsiflorus Esch. Mem. Acad. Petersb. ser. 6, 10:285 (1826), type 

 loc. California (probably San Francisco), Eschscholtz ; Sargent, Silva 2:43, t. 64 (1891) ; Jep- 

 son, Fl. W. Mid. Cal. 256 (1901), ed. 2, 253 (1911), Man. 618, fig. 618 (1925). Var. GRISKUS 

 Trel. in Gray, Syn. Fl. r:415 (1897), type loc. Monterey; Jepson, Man. 619 (1925). Var. 

 CHANDLERi Jepson, l.c, type loc. Pajaro Hills, n. Monterey Co., Chandler 402. 



9. C. arboreus Greene. Island Ceanothus. Shrub, or often a small tree, 12 

 to 20 feet high with distinct trunk and round but open crown; branches woolly- 

 puberulent; leaf -blades broadly ovate to elliptic, obtuse or acutish, rounded to 

 obscurely cordate at base, mucronate-serrulate, 1 to 3 inches long, above dark 

 green and glabrescent, beneath 3-ribbed and whitened (or light slate-color) with 

 a thin but close fine felt; panicles compound, 2 to 3V3 inches long; flowers pale blue, 

 fragrant; capsules large (4 lines broad), blackish when ripe and strongly ridge- 

 crested on the back of the lobes and strongly wrinkled all over. 



Dry hill slopes and canons: Santa Barbara Islands (Santa Catalina, Santa 

 Cruz and Santa Rosa islands). Feb. -Mar. 



Ceanothus arboreus, an insular species, is remarkable for its ample foliage, usually much 

 whitened beneath, and large leaf scars on old wood. It has long been cultivated and is a valued 

 shrub in ornamental gardens. On Santa Cruz Island we have often measured trunks 4 to 6 

 inches, in diameter. 



Locs. — Santa Catalina Isl., Gambel (who first collected it), Jepson 3062; Pelican Bay, 

 Santa Cruz Isl., Jepson 12,105; Freys Harbor, Santa Cruz Isl., A. L. Grant 1730; Santa Eosa 

 Isl., T. Brandegee. 



Eefs. — Ceanothus arboreus Greene, Bull. Cal. Acad. 2:144 (1886), type loc. Santa Cruz 

 Isl., Greene; Jepson, Man. 619 (1925). C. velutinus var. arboreus Sarg, Gard. & For. 2:364 

 (1889), Silva 2:45, t. 65 (1891). C. arboreus var. glabra Jepson, I.e., type loc. Santa Eosa Isl., 

 T, Brandegee ; herbage glabrous or nearly so. 



10. C. velutinus Dougl. Tobacco Brush. Stems several or many from the 

 base, commonly diffusely spreading and forming a low rounded shrub 2 to 5 feet 

 high, rarely tree-like and up to 12 feet high; herbage with a strong cinnamon odor; 

 leaf -blades round-ovate or elliptic, obtuse at apex, rounded or subcordate at base, 

 glandular-serrulate, 1 to 3i/^ (mostly II/2 to 2^/2 ) inches long, dark green, glabrous 

 and usually glandular-varnished above, often drying chocolate-brown, pale and 

 with a very minute close pubescence beneath, the veins puberulent, strongly 3- 

 nerved, the lateral nerves with marked marginal veins; panicles % to 3%, com- 

 monly 2 to 3 inches long; flowers white; capsules lobed at top, very sticky-glandular, 

 2 lines broad, crests small or almost none. 



Dry mountain summits and slopes, 3500 to 8500 feet: Sierra Nevada from 

 Tulare Co. to Modoc Co.; North Coast Ranges from Humboldt Co. to Siskiyou Co. 

 North to Washington, east to Colorado and South Dakota. May-July. 



Field note. — Ceanothus velutinus forms extensive brush fields on the mountain summits and 

 plateaus in the northern Sierra Nevada from Sierra Co. to Shasta Co. and thence west to the 

 Marble Mountain country in western Siskiyou Co. It is commonly the first species to take pos- 

 session of cleanly logged or fire-burned areas and assists materially in giving something of the 

 aspect of a desert to forest-denuded slopes of the Sierra Nevada. Likewise in the Siskiyou Mts. 

 one may ride on the trails for miles through and often under a dense Ceanothus velutinus cover. 

 In the northern regions, it is usually called Snow Brush. Along the Mendocino coast the var. 

 laevigatus with its sticky upper leaf surface is known to the folk as "Greasewood". 



Locs. — Sierra Nevada: Kern Canon above Junction Camp, Jepson 1057; Mt. Dana, Eille- 

 brand; Silver Mt., J. Ball; Angora Eidge, Eldorado Co., Ottley 858; Mt. Tallac, Jepson; Tahoe 



