ROSACE 'A E. 509 



>cnOW, 12-20 mm. broad; bractlets much shorter than the erect lanceolate calyx- 

 lobes ; petals obovate or orbicular, often slightly emarginate, spreading ; i.tyle 

 plumose below, naked above, 12-16 mm. long, not jointed. White Mountains of 

 N. H. ; Mt. Kineo, Me. July- Aug. [Geum Peckii Pursh.] S. radiata (Michx.) 

 Greene, of N. Car. and Tenn., with which this has been confused, is stouter and 

 more hairy and has broadly and deeply obcordate petals. 



2. Sieversia ciliata (Pursh) Rydb. Long-plumed Purple Avens. (I. F. f. 

 1942.) Softly pubescent, scapose ; scape 1-4.5 dm. high, simple, 3-8 flowered at 

 the summit. Basal leaves petioled, interruptedly pinnate with many small leaflets 

 interspersed among the obovate or oval laciniate numerous larger ones ; leaves of 

 the scape 2 opposite small sessile pairs, the elongated peduncles commonly bearing 

 another similar pair ; flowers 12-18 mm. broad ; style 3-5 cm. long. In dry or 

 rocky soil, Lab. and northern N. Eng. to N. Y., Br. Col, Mo. and Ariz. [Geum 

 filiation Pursh.] May-July. 



20. DRYAS L. 



Low tufted herbaceous shrubs, with simple petioled stipulate leaves, white- 

 canescent beneath, and white or yellow, perfect solitary flowers on slender scapes. 

 Calyx persistent, not bracted, its tube concave, glandular-hirsute, 8-9-lobed. Pet- 

 als 8 or 9, obovate, larger than the calyx-lobes. Stamens 00 , inserted on the 

 throat of the calyx; filaments subulate. Carpels 00, sessile, inserted on the dry 

 receptacle; style terminal, persistent, elongated and plumose in fruit. Seed as- 

 cending, its testa membranous. [Name Latin, a wood- nymph. J Three species, 

 natives of the cold-temperate and arctic parts of the north temperate zone. 



Flowers white; sepals linear-lanceolate. 



Leaves oval or ovate, coarsely crenate. 1. D. octopetala. 



Leaves ovate, or ovate-lanceolate, subcordate, entire or nearly so. 



2. D. integrifolia. 

 Flowers yellow; sepals ovate ; leaves crenate. 3. D. Drummondii. 



i. Dryas octopetala L. White Mountain Avens. (I. F. f. 1949.) Stems 

 prostrate, branched, 7— 15 cm. long. Stipules linear, adnate to the petiole; leaves 

 green and glabrous above, generally obtuse at each end, 1-2.5 cm - l° n g > scape 

 terminal, erect, 3-12 cm. long, pubescent; petals spreading; sepals glandular-pubes- 

 cent, persistent ; style about 2.5 cm. long, plumose and conspicuous in fruit. 

 Lab., Greenland and arctic Am., south in the Rocky Mts. to Utah and Colo. 

 Also in arctic and alpine Europe and Asia. June-Aug. 



2. Dryas integrifolia Vahl. Entire-leaved Mountain Avens. (I. F. f. 

 1950.) Similar to the preceding, but the leaves are ovate or ovate-lanceolate, ob- 

 tuse and often subcordate at the base, obtusish at the apex, entire or with 1 or 2 

 teeth near the base, the margins strongly revolute ; flowers generally slightly 

 smaller. "White Hills of N. H.," according to Pursh; Anticosti, Lab., west 

 through arctic Am. to Alaska, and in Greenland. June-Aug. 



3. Dryas Drummondii Richards. Drummond's Mountain Avens. (I. F. f. 

 1951.) Similar to D. octopetala, the leaves crenate-dentate, but generally narrowed 

 at the base. Scape floccose-pubescent, often taller; petals generally erect; sepals 

 ovate, acutish, black glandular-pubescent. On gravel, Gaspe, Quebec; Anticosti 

 and Lab., throughout arctic America and south to Mont. June-Aug. 



21. CERCOCARPUS H. B. K. 



Shrubs or small trees, with alternate simple petioled coriaceous stipulate 

 straight-veined leaves, and short-pedicelled or sessile, axillary or terminal, perfect 

 flowers. Calyx narrowly tubular, persistent, contracted at the throat, 5-lobed. 

 Petals none. Stamens 15-25, inserted in 2 or 3 rows on the limb of the calyx; 

 filaments very short. Ovary 1, terete, slender, included in the calyx-tube, ripening 

 into a villous achene; style filiform, villous, persistent, plumose and elongated in 

 fruit; stigma obtuse; ovule nearly erect. Seed linear, its testa membranous. 

 [Greek, tailed-l'ruit.] About 6 species, natives of western N. Am. and Mexico. 



I. Cercocarpus parvifolius H. & A. Small-leaved Cercocarpus. 

 (I. F. f. 1952.) A low branching shrub. Leaves obovate or oval, coriaceous, 



