POLYGONACEAE (BUCKWHEAT FAMILY) 8l 



DD. Inner perianth segments in fruit 4-9 mm. wide, 6-10 mm. long. 

 E, All inner perianth segments in fruit without cork. 

 F. Leaves crisped, oblong, truncate at base. W. E. 



R. occldentalls (western dock) 

 FF. Leaves flat, lanceolate, rounded at base. E. R. hesperius 



EE. One inner perianth segment in fruit with cork. E. 



R. patientia (patience dock) 

 CC. Each inner perianth segment in fruit with a cork-. 

 G. Inner perianth segments in fruit 3-6 mm. wide. 

 H. Stems tufted, ascending; leaves flat, not crisped. W. E. 



R. m,exicanus (willow dock) 

 HH. Stems mostly not tufted, erect; leaves crisped at margin. W. E. 



R. crispus 

 GG. Inner perianth segments in fruit scarcely •> mm. wide; leaves somewhat 

 crisped. W. R. conglomeratus (ring-seed dock) 



BB. Inner perianth segments in fruit with slender teeth. 

 I. Perennial; teeth of inner perianth segments more than 4, shorter than the seg- 

 ments are wide; fruit mostly with 1-2 corks. 

 J. Stems sparingly branched; often some of the lower leaves fiddle-shaped; 

 inner perianth segments with 10-20 teeth. W. R. pulcher (piddle dock) 



J J. Stems branched at every joint; none of the leaves fiddle-shaped; inner 

 perianth segments with 6-10 teeth. W. E. R. obtusifoUus (bitter dock) 



n. Annual; teeth of inner perianth segments 4, longer than the segments are wide; 

 fruit with 3 corks. W. C. R. persicarioides (golden dock) 



AA. Slender plants, 4 dm. or less high, very sour; flowers dioecious. 

 K. Leaves gradually narrowed at base, not hastate, spatulate or lanceolate; pedicels 

 jointed at the base; inner perianth segments winged in fruit; akene smooth. C. E. 



R. paucifolius (mountain dock) 

 KK. Leaves hastate, oblanceolate; pedicels jointed at the summit; inner perianth- 

 segments not winged in fruit; akene granular. W. C. E. — A bad weed of ranges 

 and waste places. R. acetosella (field sorrel) 



POLYGONUM (Knotweed) 



Herbs or shrubs, annual or perennial, terrestrial or aquatic. Stems erect 

 or prostrate or climbing or floating. Leaves alternate, sessile or petioled. 

 Inflorescence various, terminal or axillary. Flowers small, normally per- 

 fect, green or white or pink or purple; pedicels not jointed. Perianth 4-6- 

 parted or -cleft. Stamens 3-9; filaments glabrous. Style 2-3-parted or 

 -cleft. Fruit lens-shaped or 3-angled, rarely 4-angled. — (Gk. polys = 

 many, gonu = knee, joint ; because the stems are distinctly many- jointed.) 



A. Plants erect to prostrate, but not vines; leaves cordate to attenuate at base. 

 B. Leaf blade jointed to the petiole (except those included in CC), less than i cm. 

 wide (except one in D); sheath 2-lobed, becoming lacerate; flowers either in 

 axillary fascicles or in spikelike racemes with non-scarious bracts. 

 C. Leaf blade not longitudinally 3-veined, jointed to the petiole. 

 D. Plants annual, glabrous or not; stems not woody, greenish, mostly striate, 



not scaly. — Large but difficult group. (F. & R. pp. 136-138.) 

 DD. Plants perennial, glabrous; stems shrubby, chestnut-brown; bark loose- 

 scaly. 

 E. Seacoast plant, in sandy soil; leaves strongly revolute; sheaths 12-21 mm. 

 long; flowers in subspicate clusters near the ends of the branches. W. 



P. paronychia (shrub knotweed) 



a. & R. EL. FL. — 6 



