ROSACEAE (ROSE FAMILY) 131 



A. Leaf segments and their lobes acute; terminal leaflet cuneate-obovate; receptacle 

 downy-pubescent. E. G. strictum (YELLOW AVENS) 



AA. Leaf segments and their lobes obtuse; terminal leaflet broadly cordate; recep- 

 tacle nearly naked. W. C. E. G. macrophyllum (LARGE-LEAVED AVENS) 



SIEVERSIA 



Perennial; stem simple. Leaves mostly basal; basal leaves pinnate. 

 Flowers in terminal cymes. Calyx deeply 5-cleft. Stamens many. Re- 

 ceptacle dry. Pistils many; style straight. (Honor of J. Sievers, a 

 Russian traveler.) 



A. Flowers pale purplish; style plumose; plant hairy; stem leaves not pinnatifid. 

 W. C. E. S. ciliata 



AA. Flowers yellow; style glabrous; plant glabrous or nearly so; stem leaves pinnati- 

 fid. E. S. rossii 



CERCOCARPUS (MOUNTAIN MAHOGANY) 



Shrubs or small trees. Leaves alternate, evergreen; stipules small, 

 wholly adnate. Flowers axillary, solitary. Calyx tube long and pedicel- 

 like; segments 5, short, deciduous. Stamens 15-25, on the calyx. Pistil i, 

 simple, free, erect; style terminal, villous. Akene linear-oblong, terete, 

 villous. (Gk. kerkos = a tail, karpos = a fruit ; referring to the long- 

 tailed akenes.) 



A. Leaves resinous, i-veined, margin revolute. 



B. Shrub; leaves linear, 2-4 cm. long; calyx lobes not half as long as the throat; 



tails of the akenes 2.5-5 cm. long. E. C. intricatus 



BB. Shrub or small tree; leaves oblong-lanceolate, 4-6 cm. long; calyx lobes as 



long as the throat; tails of the akenes 5-7.5 cm. long. E. C. ledifolius 



AA. Leaves not resinous, pinnately veined, margin not revolute. U. E. 



C. parvifolius 



RUBUS (BLACKBERRY, RASPBERRY) 



Shrubs or herbs, erect or trailing, 'often prickly. Leaves simple or pin- 

 nately 3-7-foliolate ; stipules adnate. Flowers white or purple. Calyx 

 5-lobed, persistent. Petals conspicuous. Stamens many on the calyx. 

 Carpels few to many, becoming drupelets ; style nearly terminal, deciduous. 

 Drupelets usually adhering into a compound berry. (L. ruber = red ; 

 from the fruit ; hence L. rubus = a bramble.) Fruits edible. 



A. Leaves 3-s-lobed or rarely -parted. 



B. Stem erect, 9-24 dm. high; shrub, not prickly; leaves 10-30 cm. long; fruit of 



many drupelets. W. C. E. R. parviflorus (THIMBLEBERRY) 



BB. Stem trailing, 0.5-12 dm. long; leaves 2.5-7.5 cm. long; fruit of 1-5 drupelets. 



C. Vine shrubby, with small recurved prickles; leaves shining, veins and petioles 



with recurved prickles beneath; carpels glabrous. W. C. E. R. nivalis 



CC. Vine herbaceous, without prickles; leaves not shining, not prickly; carpels 



tomentose. W. C. R. lasiococcus 



AA. Leaves 3-s-foliolate. 



D. Herbaceous vine, trailing, without prickles. W. C. E. R. pedatus 



