I30 ROSE FAMILY 



of its range and in protected places the stems are tall, the 

 leaves broad, and the petals are often much longer than the 

 calyx. This form, which grows at Hog Ranch and in Fresno 

 County, has been called Drymocallis gracilis Rydb. 



8. HORKELIA. 



Perennial herbs with pinnately compound leaves and yel- 

 low or white flowers in close terminal clusters (sessile, or 

 pedicels shorter than calyx). Calyx cup-shaped, with 5 main 

 teeth alternating with 5 tooth-like bractlets. Petals 5, wedge- 

 shaped to linear. Stamens 5 to 15, inserted on the calyx- 

 throat and therefore well separated from the receptacle; fila- 

 ments either filiform or dilated. Pistils 2 to numerous, on a 

 permanently dry conical receptacle, becoming akenes. — Aside 

 from the technical characters, our species differ from Poten- 

 tilla in having smaller flowers in more compact clusters. 



Flowers white. 



Stamens 10; filaments broad. 



Leaflets 11 to 17 1. H.fusca. 



Leaflets 5 to 9 2. H. tridentata. 



Stamens about 15; filaments thread-like 3. H. unguiculata. 



Flowers yellow; stamens 5 or 10. 



Leaves green 4. H. gordonii. 



Leaves densely white-silky, worm-like 5. H. muirii. 



1. H. fusca Lindl. Stems mostly 1 to \ x / 2 ft. high, purplish 

 or green. Leaves 3 to 5 in. long, including petiole, somewhat 

 glandular, either green or whitish pubescent; leaflets 11 to 17, 

 wedge-shaped, Y^ to l / 2 in. long, the upper portion deeply 

 toothed or cut into acute divisions. Flowers white, the calyx 

 purplish. (Potentilla douglasii Greene.) Var. tenella Wats., is 

 the more slender form, 6 in. to 1 ft. high, the flowers smaller 

 (Horkelia tenella Rydb., H. parvifiora Nutt, and Potentilla 

 andersonii Greene). 



This plant has numerous leaves at base but passing up the 

 stem they become fewer and smaller. In the Yosemite and 

 at Hog Ranch the foliage is green and glandular; at Lake 

 Tenaya, where it covers exposed slopes, the foliage is almost 

 white with soft hairs. 



2. H. tridentata Torr. Stems 9 to 18 in. high. Leaves 1 to 

 3 in. long including petiole, always white or gray with silky 

 hairs; leaflets 5 to 9, linear to obovate, ^ to ^ m - long, 

 entire or three-toothed at apex (rarely 4 or 5-toothed). 

 Petals oblanceolate, white, slightly exceeding the sepals. {Po- 

 tentilla tilingii Greene.) 



The silky pubescence and few teeth of the leaflets best mark 



