go POLYGONACEAE (BUCKWHEAT FAMILY) 



D. Akene lens-shaped; involucre 3-4-lobed, shortly awned; annual. E. 

 (Gk. oxys = sharp, theke = sac or case; referring to the pointed anthers.) 



Oxytheca dendroidea 

 DD. Akene 3-angled; involucre 4-8-lobed, pointless; annual or perennial. 



ERIOGONUM (p. 80) 

 BB. Stipules scarious and sheathing; flowers not involucrate; juice usually sour 



or acrid ; styles 2-3 ; stamens fewer than 9 (except sometimes in Polygonurri) . 

 E. Leaves kidney-shaped, wider than long; akene orbicular and broadly winged; 

 perianth lobes 4; stigmas 2. W. C. E. (Gk. oxys = sharp or sour; the leaves 

 are sour.) Oxyria digyna (MOUNTAIN SORREL) 



EE. Leaves not kidney -shaped, longer than wide; akene 3-angled or lens- 

 shaped, not winged; perianth lobes 5-6 (4 in a few); stigmas 2-3. 

 F. Perianth lobes 6, outer smaller and reflexed, inner erect and enlarging in 

 fruit (except R. acetosella with very sour leaves); stigmas 3, tufted; akene 

 3-angled. RUMEX (p. 80) 



FF. Perianth lobes 5, rarely 4 or 6, all about equal and remaining so; stigmas 



2-3, capitate; akene 3-angled or lens-shaped. 



G. Plants vines; akene 3-angled. POLYGONUM (p. 81) 



GG. Plants not vines; akene 3-angled or lens-shaped. 



H. Plants not fleshy; calyx exceeding the mature akene; surface of akene 

 without pinnate striation; basal angles of leaves either projecting downward 

 or else rounded. POLYGONUM (p. 81) 



HH. Plants rather fleshy; calyx only \ as long as the akene; mature akenes 

 with pinnate striation on each face; basal angles of leaves pointed, the points 

 projecting outward. W. Cultivated for honey and flour. (Gk. phagos 

 = edible, or the beech; pyros = wheat; the seed resembles a beechnut.) 



Fagopyrum esculentum (CULTIVATED BUCKWHEAT) 



ERIOGONUM (ERIOGONUM) 



Herbs or shrubs or shrubbery at base. Stems often tufted. Leaves 

 entire. Flowers in clusters; clusters involucrate. Perianth 6-cleft or 

 -parted, usually colored. Plants mostly of dry plains. (Gk. erion = 

 wool, gonu = knee ; on account of the woolly and jointed stems.) 



RUMEX (DOCK) 



Herbs, juice more or less sour or acrid. Stem grooved. Leaves 

 alternate, flat or crisped, entire or undulate ; stipules sheathing. Flowers 

 small, green, in racemose or paniculate whorls or fascicles. Perianth 

 6-parted or of 6 distinct segments, more or less colored, the inner often with 

 cork swellings in fruit. Stamens 6. Fruit inclosed in the 3 inner perianth 

 segments. (L. rumo = to suck ; because the Romans sucked the leaves 

 to allay thirst.) The leaves of most species are sometimes used for greens. 



A. Coarse plants, usually over 4 dm. high, not strongly sour; flowers not dioecious. 

 B. Inner perianth segments in fruit entire, or merely erose or undulate. 

 C. None or only r of the inner perianth segments in fruit with cork. 

 D. Inner perianth segments in fruit 15-37 mm. wide, 20-40 mm. long, without 

 corks; leaves flat. E. R. venosus (BIG-SEED DOCK) 



