164 



American Midland Naturalist Monograph No. 4 



Differs from the above variety in having leaves softly hairy on both sides. 



Occurrence. — YOSEMITE, about 4,000 feet: Hetch Hetchy; Yosemile Valley; Wa- 

 wona. KINGS CANYON: Kings River Canyon; near Charlotte Creek. SEQUOIA: vicinity 

 of Mineral King. 



5. Whiteleaf Buckthorn 

 (Rhamnus tomentella Benth.), 

 fig. 95. — Robust evergreen shrub 

 4 to 6 (or 10) feet high with 

 gray or brown branches and leaves 

 scattered along the branchlets in 

 contrast to those of cascara buck- 

 thorn which are clustered towards 

 the ends of the branchlets; leaves 

 thickish, narrowly elliptic to ob- 

 long or lance-shaped, 2 to 3 inches 

 long, abruptly pointed at the tips, 

 the margins finely toothed or not 

 toothed, prominently veined and 

 densely hairy below with line gray- 

 ish or yellowish hairs; flowers 

 small, greenish, borne in small 

 clusters in the leaf -axils; berries I/4 

 to 1/3 inch in diameter, round or 

 oval, becoming reddish and then 

 black, usually containing 2 nutlets. 

 (Syn. R. californica Eschsch. var. 

 tomentella Brew. & Wats.). 



The species is found usually 

 in rocky soil on warm dry slopes, 

 often growing to large shrubs with 

 dense rounded crowns, especially in openings in the chaparral. 



Occurrence. — YOSEMITE, 2,000 to 4,000 feet: Merced Falls. KINGS CANYON: Gen- 

 eial Grant Grove. SEQUOIA, 4,500 feet: Marble Fork Kaweah River; Clough Cave; 

 west of Ash Mountain just outside park boundary. 



Fig. 95. Whiteleaf buckthorn 

 {Rhamnus tomentella). 



6. HoLLYLEAF Redberry Buckthorn (Rhamnus crocea Nutt. var. 

 ilia folia (Kell.) Greene). — Branched evergreen shrub 3 to 12 feet high with 

 short stout often spine-tipped branches, or sometimes tree-like; leaves elliptic 

 to roundish, 1/3 to 1 inch long, stiff and leathery, holly-like, with spine-toothed 

 margins, smooth above, yellowish-green below; flowers 1 to few in the leaf- 

 axils, without petals; berries oval, about ^4 ^^^^ ^o^^gj bright red when ripe, 

 usually with 2 seeds. 



Occurrence. — YOSEMITE, rare, 6,000 feet: near El Portal; Yosemite Valley; foot 

 of Yosemite Falls; north side of Muir Gorge; Hetch Helchy Valley. SEQUOIA, occa- 

 sional, 2,500 to 4,200 feet: Colony Mill trail; highway between Ash Mountain and 

 Advance Camp; east of Hospital Rock; 3 miles west of Hidden Springs ranger sta- 

 tion; j/2 mile east of Clough Cave. 



