246 EOSACEAE (kose family) 



stamens inserted near base of calyx, near to the re- 

 ceptacle 23. Potentilla, 



Receptacle somewhat enlarged-spongy .... '24. Comarum, 

 Leaves compound; style persistent on the achene. 



Style jointed; the upper part deciduous .... 25. Geum. 



Style not jointed i . . 26. Sieversia, 



Fruit inclosed in the persistent receptacle, i. e,, the calyx is con- 

 stricted over the fruit. 

 Herbaceous; receptacle dry. 



Calyx with hooked prickles 27. Agrimonis, 



Calyx not prickly 28. Sanguisorba. 



Shrubby; receptacle fleshy 29. Rosa. 



1. CERCOCARPUS H.B.K. Mountain Mahogany 



Shrubs or small trees, with simple evergreen leaves. Flowers small, axil- 

 lary, solitary. Calyx without bractlets; its tube long, cylindrical. Corolla 

 wanting. Stamens 15-25, in 2 or 3 rows on the deciduous Umb of the calyx. 

 Fruit coriaceous, linear, terete, villous, included in the enlarged oalyi-tube 

 and tailed with the elongated and plumose style. 



Leaves not resinous, obovate . . ..... 1. C. parvifolius. 



Leaves resinous, narrow. 



Oblong-lanceolate, 4-6 cm. long 2. C. ledifolius. 



Linear, 2-4 cm, long 3. C. intricatus. 



1. Cercocarpus parvifolius Nutt. H. & A. Bot. Beechey Voy, 337. 1841. 

 A shrub 6-30 dm. high (sometimes twice as high): leaves cuneate-obovate, 

 coriaceous, serrate towards the obtuse or rounded sunmiit, more or less silky 

 above, densely hoary-tomentose beneath: flowers on short slender pedicels: 

 limb of calyx with short teeth: tail of achene often 10 cm. long.^Bleak stony 

 slopes; from the plains east of the Rocky Mountains to the Pacific. 



2. Cercocarpus ledifoUus Nutt. T. & G. Fl. N.A. 1: 427. 1840. A shrub 

 or small tree, 1-3 m. high: leaves entire, oblong-lanceolate, 4-6 cm. long, 

 thick-coriaceous, margins more or less revolute, nearly glabrous and some- 

 what resinous above, densely tomentose beneath: flowers sessile, tomentose, 

 solitary or 2-3 in the axils: calyx deeply toothed: tail of the achene at length 

 4-7 cm. long. — Utah, western Wyoming, and west to California. 



3. Cercocarpus intricatus Wats. Proc. Am. Acad. 10: 346. 1875. A low 

 shrub, rarely more than 1 m. high, intricately branched: leaves linear, closely 

 revolute, about 3 cm. long; otherwise as in the preceding except that the 

 flowers and fruits are much smaller. — ^From northeastern Wyoming and 

 Montana to Utah and Nevada. 



2. COWANIA Don. Cliff Rose 



Shrubs, with small coriaceous entire or deeply toothed gland-dotted leaves. 

 Flowers showy, terminal, short-peduncled. Calyx-tube turbinate. Petals 5, 

 obovate. Stamens numerous, in 2 rows inserted with the petals at the throat 

 of the calyx-tube. Carpels about 5, densely villous. Fruit coriaceous, narrowly 

 oblong, striate, partly included in the enlarged calyx-tube, and tailed with 

 the elongated plumose styles. 



1. Cowania mexicana Don. in Trans. Linn. Soo. 14: 575. 1825. A much 

 branched shrub, 3-12 dm. high; the trunk with abundant shreddy light- 

 colored bark: leaves approximate upon the short branchlets, cuneate-obovate 

 in outline, pinnately 3-7-lobed, dark green above, tomentose beneath: flowers 

 yellow, the ' calyx-tube attenuate into a short glandular-hairy pedicel: tail 

 of the achene at length 5 cm. long or more. — Northern Utah and southern 

 Colorado to central Mexico. 



3. PURSHIA DC. 



A low intricately-branched prostrate shrub, or in the far west taller and 

 erect, with fascicled cuneate leaves, and flowers terminal on the short branch- 



