222 



ROSACEAE. 

 14. DRYAS L. Sp. PI. 501. 1753. 



[Voi.. II. 



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

 neath, and white or yellow, rather large perfect solitary flowers on slender scapes. Calyx 

 persistent, not bracted, its tube concave, glandular-hirsute, S-g-lobed. Petals 8 or 9, obovate, 

 larger than the calyx-lobes. Stamens oo, inserted on the throat of the calyx; filaments subu- 

 late. Carpels so , sessile, inserted on the dry receptacle; style terminal, persistent, elongated 

 and plumose in fruit. Seed ascending, its testa membranous. [Name Latin, a wood- 

 nymph.] 



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



Flowers white ; sepals linear. 



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



Leaves ovate, or ovate-lanceolate, subcorclate, entire or nearly so. 2. D. integrifolia. 



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



i. Dryas octopetala L,. White Mountain Avens. (Fig. 1949.) 



Dryas oclopetala I.. Sp. PI. 501. 1753. 

 Dryas chamaedrifolia Pers. Syn. 2: 57. 1807. 



Stems prostrate, woody at the base, 

 branched, 3 / -6 / long. Stipules linear, ad- 

 nate to the petiole; leaves oval or ovate, 

 coarsely crenate all around, green and gla- 

 brous above, densely white-canescent be- 

 neath, generally obtuse at each end, %'-i r 

 long; scape terminal, erect, I '-5' long, 

 pubescent; flower white, about i' broad; 

 sepals linear, acute or acutish, glandular- 

 pubescent, persistent; style about I'long, 

 plumose and conspicuous in fruit. 



Labrabor and Greenland and throughout 

 arctic America, south in the Rockv Mountains 

 t<> I 'tali. Also in arctic and alpine Knropt- 

 and Asia. June-Aug. 



2. Dryas integrifolia Vahl. Entire-leaved 

 Mountain Avens. (Fig. 1950.) 



Dryas integrifolia Vahl, Act. Havn. 4: Part 2, 171. 1798. 

 Dryas tenella Pursh, Fl. Am. Sept. 350. 1814. 



Similar to the preceding species, but the leaves are 

 ovate or ovate -lanceolate, obtuse and often subcordate at 

 the base, obtusish at the apex, entire or with i or 2 teeth 

 near the base, the margins strongly revolute; flowers 

 white, generally slightly smaller; sepals linear. 



"White Hills of New Hampshire," collected by Prof. 

 Peck, according to Pursh; Anticosti, Labrador, west through 

 arctic America to Alaska, and in Greenland. June-Aug. 



