82 POLYGONACEAE. 



or panicles; petals none; calyx free from the ovary, 2-6-cIeft or 

 parted, the segments sometimes petal-like; stamens 4-9, inserted 

 near the base of the calyx or in staminate flowers crowded toward 

 the center; pistil 1; ovary superior, 1 -celled; ovule 1; fruit a 

 lenticular or 3-angled, rarely 4-angled akene; endosperm mealy. 



Flowers subtended by involucres. 113. Eriogonum, 82. 

 Flowers not subtended by involucres. 



Sepals 6; stigmas 3, tufted. 114. Rumex, 83. 



Sepals 4-6, usually 5; stigmas capitate. 115. Polygonum, 85. 



113. ERIOGONUM. 



Annual or perennial acaulescent or leafy-stemmed herbs or 

 shrubs; stems simple or branched, often tufted; leaves entire, 

 alternate or whorled; flowers small, fascicled, cymose, umbellate 

 or capitate, subtended by 5-8-toothed or cleft campanulate or 

 cylindric involucres; calyx 6-cleft or parted, usually colored; 

 segments equal or the outer ones larger; stamens 9; akenes 

 pyramidal, 3-angled, more or less swollen near the base, invested 

 by the calyx-segments or winged. 



Flowers attenuate and stipe-like at base. 



Perianth very pubescent; umbel simple, dense. 



Involucre with reflexed lobes; flowers cream-color. E. douglasii. 



Involucre with erect lobes; flowers yellow. E. piperi. 



Perianth glabrous or nearly so; umbel usually compound. 



Leaves large, mostly cordate. E. compositum. 



Leaves small, never cordate. 



Flowers bright yellow; leaves oval, glabrous above. E. stellatum. 

 Flowers white; leaves lanceolate, tomentose on both 



sides. E. heracleoides 



Flowers not attenuate and not stipe-like at base. 



Outer perianth-segments much broader than the inner. E. niveum. 

 Outer perianth-segments like the inner. 



Annual; stems wiry; leaves orbicular, in a rosette. E. vimineum. 



Perennial; stems woody; leaves narrower. E. strictum. 



Eriogonum douglasii Benth. Prostrate or nearly so, only the flowering 

 stems upright; leaves in tufts on woody caudex branches, small, 1-2 cm. long, 

 oblong or spatulate, not revolute; flowers cream-color, in simple spherical, 

 head-like umbels, attenuate and stipe-like at base; perianth pubescent; 

 involucre short with linear reflexed lobes. Blue Mountains, rare. 



Eriogonum piperi Greene. Densely tufted on a stout woody caudex; stems 

 erect, leafless, tomentose, 10-20 cm. tall; leaves all basal, lanceolate or ob- 

 lanceolate, acute or obtuse, white* and densely hairy beneath, green and less 

 hairy above; blade 2-4 cm. long, attenuate into a usually shorter petiole; 

 umbels several-rayed, simple or contracted into a dense cluster; bracts 3-8, 

 oblanceolate, 1-3 cm. long; involucre short-toothed, villous; flowers yellow, 

 very villous, 5-6 mm. long. In rocky places at high altitudes. 



Eriogonum compositima Dougl. Stems stout, simple, 20-30 cm. tall, 

 glabrous or nearly so; leaves ovate or oblong-ovate, cordate, acute, densely 

 white- woolly beneath, green and less so above, 4-10 cm. long, on petioles as 



