BUCKTHORN FAMILY. 255 



branches and branchlets, the latter more or less modified into thick stout thorn- 

 like spurs; leaves elliptic to ovate, acute or obtuse, rounded at base, light 

 colored above, strongly 3-nerved and whitish or pale beneath, 1 to \l/ 2 in. 

 long; petioles 2 or 3 lines long; inflorescence finely velvety, 2 or 3 in. long 

 or less; flowers white; capsules thickly warty, shallowly lobed at top, 2U 2 lines 

 in diameter. 



Brushy openings or peaks in the Eedwood belt from the Santa Cruz Mts. 

 to Mt. St. Helena and northward through the Eedwoods of Mendocino and 

 Humboldt cos., less common or absent eastward in the ' ' Bald Hills ' ' country. 

 Called " White Thorn' ' in southwestern Humboldt. 



C. cordulatus Kell. Snow Brush. Low flat-topped spreading shrub, with 

 whitish twigs and spinose branchlets; leaves broadly elliptic, cuneate to sub- 

 cordate at base, 6 to 9 lines long, dark green above, minutely puberulent; 

 flowers white, in short racemes. — Sierra Nevada, very abundant at 6000 to 

 9000 ft., forming open thickets. 



10. C. cuneatus Nutt. Buck Brush. Rigid divaricately branched shrub 

 of a gray-blue hue, 5 to 8 ft. high; bark whitish; branchlets stout and short, 

 those on a branch often very unequal and frequently interruptedly disposed; 

 leaves oblong-obovate to broadly obovate, entire, green above, paler beneath, 

 4 to 6 (or 11) lines long, on very short petioles; umbels 6 to 9 lines broad; 

 pedicels 2 to 4 lines long; flowers white; capsules slightly oblong, 2y 2 lines 

 long, with three short erect horns. 



Very abundant on dry or rocky slopes in the higher Coast Eanges and in 

 the Sierra Nevada foothills, either isolated, or gregarious and one of the 

 constituents of the chaparral. Also called Blue Brush. Chaparral consists of 

 Manzanita, Pickeringia, Buck Brush, Scrub Oak or similar shrubs which form 

 impenetrable and extensive thickets clothing densely the higher slopes and 

 ridges of the Coast Eanges, and the foothills and middle altitudes of the 

 Sierra Nevada. Mar.- Apr. 



11. C. rigidus Nutt. Shrub 4 to 6 ft. high, rigidly and intricately 

 branched; leaves opposite and crowded, cuneate-obovate, mostly retuse, firm 

 but rather thin, soon nearly glabrous on both surfaces, the apical half finely 

 spinose-dentate, 2 to 6 lines long, nearly sessile; stipules conspicuously warty; 

 flowers bright blue; capsules a little larger than in no. 10. 



Eare: Mt. Tamalpais and Bolinas Eidge to Monterey. 



12. C. jepsonii Greene. Eignl erect shrub about 4 to 5 ft. high; branch- 

 lets short, stubby, gray; leaves elliptic-oblong, spiny-toothed, undulate-margined 

 or somewhat infolded longitudinally, 4 to 9 lines long; stipules small; flower- 

 clusters small, the pedicels 2 or 3 lines long; flowers white or blue, exhaling 

 a musky odor. 



Mt. St. Helena; Howell Mt. ; Marin Co. Feb.-May. 



13. C. purpurea Jepson. Erect shrub 4 or 5 ft. high with brownish or 

 reddish branchlets; leaves very thick, orbicular, 1 in. long or less, glabrous, 

 shining and light green above, paler beneath with a closely appressed tomen- 

 tum, coarsely and pungently toothed all around; stipules very large; flowers 

 large, purple; pedicels 5 to 7 lines long; fruit unknown. 



Napa Eange. May. Nearly allied to C. CBASSEFOLTUS Torr. (San Diego 

 Co. northward to the Santa Inez Mts.) which has elliptic-obovate leaves with 

 more finely toothed or subentire revolute margin, the upper surface roughened, 

 the lower surface densely white tomentose; capsules subglobose, with 3 stout 

 suberect horns near the top, 3 to 4 lines in diameter. 



14. C. prostratus Benth. Mahala Mats. Branches prostrate, rooting, 



