ARISTOLOCHIACEAE. 125 



156. ASARUM. WILD GINGER. 



Stemless perennial often clustered herbs, with slender aromatic 

 branched rootstocks', roots thick, fibrous-fleshy; leaves long- 

 petioled, reniform or cordate, entire; flowers solitary, large, 

 peduncled, brown-purple or mottled, borne near the ground; 

 calyx bell-shaped or hemispheric, adnate to the ovary, at least 

 below, regularly 3-lobed; stamens 12, inserted on the ovary; 

 ovary partly or wholly inferior, 6-celled, the parietal placentae 

 intruded; ovules numerous; capsule coriaceous; seeds compressed. 



Asarum caudatum Lindl. Sparsely hairy throughout; rootstocks elongate, 

 10-30 cm. long; leaves reniform-cordate, 5-10 cm. broad, obtuse or acutish; 

 petioles slender, elongate; peduncles 1-4 cm. long; flowers brown-purple; 

 calyx-lobes oblong-lanceolate, attenuate, 2-5 cm. long. 



In woods, common, the whole plant with the faint odor of ginger. 



Family 33. POLYGONACEAE. BUCKWHEAT FAMILY. 

 Herbs or shrubs; leaves alternate or sometimes opposite or 

 whorled, simple, mostly entire, with usually sheathing united 

 stipules (ocreae); flowers small, regular, perfect, dioecious, 

 monoecious or polygamous, in spikes, racemes, corymbs, umbels 

 or panicles; petals none; calyx free from the ovary, 2-6-cleft 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 involucrate; stipules wanting. 157. ERIOGONUM, 125. 



Flowers not involucrate; stipules sheath-like. 



Leaves reniform; sepals 4. 158. OXYRIA, 126. 



Leaves not reniform; sepals 6. 



Sepals unequal, the inner becomming much 



larger; stigmas tufted. 159. RUMEX, 127. 



Sepals equal; stigmas capitate. 160. POLYGONUM, 128. 



157. ERIOGONUM. 



Annual or perennial acaulescent or leafy-stemmed herbs or 

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

 alternate or whorled; flowers small, in fascicles, subtended by a 

 5-8-toothed or cleft campanulate or cylindric involucre; inflo- 

 rescence cymose, umbellate or capitate; 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. 



The species in our limits are all perennials. 



Perianth not attenuate into a slender stipe-like base. 



Outer perianth-segments like the inner. E. nudum. 



