102 



RHAMNACE^. Ceanothus. 



5. CEANOTHUS, Liim. 



Calyx 5-cleft ; tlie lobes acute, connivent ; disk thick, adnate to the turbinate or 

 -hemispherical tube aud to the ovary. Petals ou long claws, hooded. Stamens 5 ; 

 hlameuts filiform, long-exserted. Ovary 3-lobed : style short, 3-cleft. Drupe sub- 

 globose, 3-lobed, surrounded at base by the adnate calyx-tube, soon dry ; the 3 

 crustaceous nutlets at length separating and dehiscing on the inner edge. Seed 

 obovate, convex on the back : cotyledons oval or obovate. — Shrubs or small trees, 

 sometimes spinescent ; with petioled leaves, and showy thyrsoid or cymose flowers. 

 — Watson, Proc. Am. Acad. x. 333. 



Species 28, of whicli three are Mexican and four in the Athxntic States, the others belonging 

 to the region between the Rocky Mountains and the Pacific. 



§ 1, Leaves all alternate, d-nerved or pinnateli/ veined, glandular-toothed or entire : 

 fruit not crested. — Ceanothus proper. 



* Leaves three-nerved from the base. 



-i- Erect, the branches not rigidly divaricate nor spiny : inflorescence thyrsoid : leaves 

 tis'ually large, glandnlar-serridate {except in No. 3). 



1. C. thyrsiflorus, Eschscholtz. A tall shrub or small tree, 6 to 15 feet high, 

 nearly glabruus ; branches strongly angled : leaves rather thick, oblong to oblong- 

 ovate, 1 to U inches long, usually smooth and shining above, canescent beneath: 

 flowers bright blue, in dense compound racemes, terminating the usually elon- 

 gated and somewhat leafy peduncles. — Lindl. Bot. Peg. xxx, t. 38 ; :Xutt. Sylva, 

 ii. 44, t. 57. 



In the Coast Ranges from Monterey to Humboklt County. Known as •' California Lilac " and 

 often cultivated. 



2. C. velutinus, Dougl. A stout diffusely branching shrub, 2 or 3 feet high, 

 usually glabrous : leaves thick, broadly ovate or eUiptical, 1| to 3 inches long, resi- 

 nous and shining above, sometioies velvety beneath ; petioles stout, half an inch 

 long: flowers white, in a loose thyrse: peduncles usually short. — Hook. PL i. 125, 

 t. 45, & Bot. Mag. t. 5165. 



From Northern California to the Columbia, and very frequent eastward to Colorado. 



3. C. integerrimus, Hook. & Arn. A more slenderly branched shrub, 2 or 3 

 feet high, glabrous or soon becoming so, rarely pubescent ; branches terete, usually 

 warty : leaves thin, bright green, ovate to ovate-oblong, 1 to 3 inches long, entire 

 or very rarely slightly glandular-serrulate, on slender petioles 2 to 6 lines long : 

 thyrse often large and open, terminating the slender branches or axiUary and rather 

 shortly peduncled, mostly white-flowered. — Bot. Beechey, 329. C. Californicus, 

 Kellogg, Proc. Calif Acad. ii. 55. C. Nevadensis, Kellogg, 1. c. ii. 152, fig. 45. 



Var. (?) parvifolius, Watson. Of very slender habit, wholly glabrous : leaves 

 much smaller, about half an inch long, shortly petioled : flowers light blue, m 

 rather short simple racemes. — Proc. Am. Acad. x. 334. 



Frequent in the mountains from Central California to the Columbia. The variety seeming 

 to run into the typical form, is confined to the Sierra Nevada, from Yosemite Valley northward. 



-i- +- Low, the branches not rigidly divaricate nor spiny : flowers blue, in short simple 

 racemes or pedimmlate clusters : leaves small, glandular-serrate. 



4. C. dentatus, Torr. & Gray. Erect, hirsutely pubescent or rarely nearly gla- 

 brous : leaves | to 1 inch L^ng, usually small and fascicled, obovate to oblong-elhptic 

 or lanceolate, acute at both ends or obtuse at the apex, the margin becoming strongly 

 undulate or revolute ; the smaller leaves apparently pinnate-veined and often more 

 or less resinous : flowers in small roundish clusters, on naked terminal peduncles 



