136 ROSACEAE. 



192. RUBUS. 



Perennial herbs or shrubs or vines, often prickly; leaves alter- 

 nate, simple, or pinnately 3-7-foliolate, with stipules adherent to 

 the petiole; flowers white or reddish, solitary or in racemes or 

 corymbs; calyx 5 -lobed, without bractlets; petals 5, conspicuous; 

 stamens numerous, on the calyx-tube; styles nearly terminal; 

 carpels numerous, on the convex receptacle, ripening into 1- 

 seeded drupelets forming an aggregate fruit. 



Stems trailing ; fruit not separating from the receptacle when 



ripe. R. macropetalus. 



Stems erect or ascending; fruit separating from the receptacle 

 when ripe. 

 Leaves 3-S-lobed; stems unarmed, perennial. R. parviflorus. 



Leaves 3-S-foIiolate; stems prickly, biennial. 



Berry red; stems not glaucous. R. strigosus. 



Berry black; stems glaucous. 



Leaves glaucous beneath. R^ leucodermis. 



Leaves green beneath, R. hesperius. 



Rubus macropetalus Dougl. Dewberry. Stems slightly woody, biennial, 

 prickly, trailing, 1-8 m. long, usually unbranched the first year, but bearing 

 numerous short flowering branches the second year; leaves 3-foliolate, rarely 

 5-foliolate; leaflets ovate, mostly acute, rounded or cordate at base, doubly and 

 somewhat incisely dentate, pubescent especially beneath, 2-5 cm. long; calyx 

 glandular and prickly; petals white, 1-2 times as long as the sepals which have 

 an acute somewhat foliaceous tip; fruit black when ripe, cylindrical, 1-3 cm. 

 long, finely flavored. In open woods, especially old " burns." 



Rubus parviflorus Nutt. Thimble Berry. Stems wholly unarmed, peren- 

 nial, 1-1.5 m. high; bark brownish, becoming shreddy, usually glandular- 

 pubescent when young; leaves palmately and acutely 5-lobed, irregularly 

 serrate, cordate at base, soft-pubescent or nearly glabrous, 10-30 cm. broad; 

 petioles about as long as the blades, with stipules; corymbs few-flowered; 

 calyx glandular and woolly; petals white, about 2 cm. long; fruit red, flat- 

 convex, juicy, about 2 cm. broad. Common in open woods; rare away from 

 timber. 



Rubus strigosus Michx. Red Raspberry. Stems erect, biennial, 1-2 m. 

 high, densely armed with weak, glandular bristles or sometimes nearly un- 

 armed; leaves mostly 3-folioIate, rarely 5-foliolate; leaflets ovate, acuminate, 

 simply or doubly dentate, rounded at base, thin, usually white-tomentose 

 beneath, glabrous above, 2—6 cm. long; corymbs few-flowered; calyx usually 

 pubescent and bristly; petals white, about as long as the acuminate sepals; 

 fruit hemispherical, light red. In low woods and on talus slopes. 



Rubus leucodermis Dougl. Blackcap. Erect shrubs; the biennial stems 

 1-2 m. high, very glaucous, armed with stout straight or curved prickles; 

 leaves 3-foliolate, rarely 5-foliolate; leaflets ovate, acuminate, doubly ser- 

 rulate, white-pubescent beneath, the lateral ones oblique and frequently with 

 one or two lobes; petioles and midveins prickly; flowers small, in few-flowered 

 corymbs; petals white, small, erect, shorter than the reflexed sepals; fruit 

 nearly black when mature, hemispherical, glaucous or tomentose, about 1 cm. 

 broad. In wet places in woods. 



Rubus hesperius Piper. Much like R. leucodermis but with more numerous 

 stouter straight or curved prickles; leaves green and glabrous on both sides; 

 berries black, glabrous. Snake River canyon. 



