ROSE FAMILY 151 



(y) Leaflets 3-5 ; stems trailing, leafy RUBUS 

 y. Leaves pinnate of many leaflets; stems 



leafless HORKELIA 



(2) Flowers yellow, pink or purple, occasion- 

 ally cream-colored or white 



(a) Stamens 5; pistils 5-10 



x. Petals white; leaves many-cleft into 



linear segments CHAMAERHODUS 



y. Petals yellow, small ; leaves of 3 leaflets SIBBALDIA 



(b) Stamens 10-many ; pistils many 



x. Styles long, persistent and usually 



hooked or plumy in fruit 

 (x) Styles naked or plumy, bent or 



jointed ; flowers yellow or purplish GEUM 

 (y) Styles naked or plumy, straight, not 

 jointed; flowers yellow or pink- 

 purple SlEVERSIA 

 y. Style short, falling away from the ripe 



achenes 

 (x) Styles attached at the base of the 



achenes; leaflets not silvery-silky DRYMOCALLIS 

 (y) Styles lateral, attached near the 

 middle of the achene; leaflets sil- 

 very-silky ARGENTINA 

 (z) Styles terminal, attached near the 



tip of the achenes 



m. Flowers yellow POTENTILLA 



n. Flowers red-purple COMARUM 



2. Shrubs 



a. Leaves simple 



(1) Flowers solitary, or 2-3 in a cluster 



(a) Petals white; 



x. Stamens and pistils many ; leaves round- 

 ish, 3-5-lobed RUBUS 

 y. Stamens 10 ; pistils 5 ; leaves entire KELSEYA 



(b) Petals yellow 



x. Leaves 3-7-pinnatifid ; style becoming 



long and plumy COWANIA 



y. Leaves 3-lobed at tip ; style not long 



and plumy PURSHIA 



(c) Petals none 



