RHAMNACEAE. 237 



Rhamnus purshiana DC. Bearberry. Small tree, 3-12 m. high, with 

 nearly smooth dark-gray bark; young twigs pubescent; leaves elliptic, obtuse 

 or acuminate, rounded at base, somewhat undulate, denticulate, pubescent 

 especially beneath, 5-15 cm. long; petioles 1-2 cm. long, downy; umbels stout- 

 peduncled, 8-15-flowered; flowers 3-5 mm. long; sepals 5; petals minute, 

 hood-shaped; fruit black, obovoid, as large as a pea, 3-seeded, insipid. 



Common in moist or wet places. Bark used medicinally under the name 

 Cascara sagrada. 



315. CEANOTHUS. 



Shrubs, sometimes evergreen; leaves alternate, petioled; 

 flowers perfect, in small umbel-like clusters, forming dense 

 terminal panicles often on naked branches; calyx 5-lobed ; calyx 

 and disk adherent to the ovary; petals hooded, spreading; 

 stamens 5; ovary 3-lobed; fruit 3-lobed, dry and very oily, 

 the three carpels splitting apart when ripe. 



Leaves opposite, tridentate at apex. C. cuneatus. 



Leaves alternate. 



Plant gummy; leaves thick, evergreen. 



Leaves pubescent beneath. C. velutinus. 



Leaves glabrous beneath. C. velutinus laevigatus. 



Plant not gummy; leaves thin, deciduous. 



Leaves mostly entire; flowers blue or white. C. peduncularis. 

 Leaves serrate or dentate. 



Flowers white; twigs terete; leaves large. C. sanguineus. 

 Flowers blue; twigs angled; leaves small. C. thyrsiflorus. 



Ceanothus cuneatus (Hook.) Nutt. Stems erect, rigid, much branched, 

 1-4 m. high; twigs gray, tomentulose when young; leaves opposite, cuneate- 

 obovate or spatulate, obtuse or retuse at apex, denticulate to entire, 5-10 mm. 

 long, short-petioled, minutely tomentose beneath; flowers white or rarely 

 bluish, in axillary umbels; capsules oblong, each carpel with a horn-like crest 

 near the top. 



In dry or rocky ground, from the Columbia River southwards. 



Ceanothus velutinus Dougl. Sticky Laurel. Stout shrub, 1-2 m. high, 

 much branched; branchlets puberulent; leaves oval, obtuse, subcordate at 

 base, prominently 3-nerved, finely denticulate, thick and firm, glabrous and 

 gummy above, puberulent beneath, 5-8 cm. long; petioles stout; flowers white, 

 in terminal panicles 5-10 cm. long; peduncles stout, puberulent; pedicels 

 slender; carpels subglobose, 3-lobed above, nearly smooth. 



In open woods, rather common. The plant has a pleasant aromatic odor. 



Ceanothus velutinus laevigatus (Dougl.) T. & G. Leaves glabrous 

 beneath. 



Known from Vancouver Island, Menzies, Macoun, Harstine Island, Mason 

 County, Washington, southwestern Oregon and northern California. 



Ceanothus peduncularis Greene. Stems 1-2 m. high, loosely branched; 

 leaves oval-oblong, rounded at base, acute and mucronate at apex, 3-nerved, 

 pubescent on both faces, 3-6 cm. long; panicle 5-8 cm. long; peduncle elongated, 

 pubescent, its bracts oblong, acute, pubescent; bractlets ovate to lanceolate, 

 acuminate, villous. 



Washington to California. 



Ceanothus sanguineus Pursh. Buckbrush. Shrub, 1-3 m. high, with 

 slender smooth usually reddish branchlets; leaves thin, elliptical or ovate, 



