P Polygonaceae 135 
flat or crisped, entire or undulate; stipules sheathing. Flowers small, green, perfect or 
polygamous or dioicous, on jointed pedicels, in racemose or paniculate whorls or fascicles. 
Perianth 6-parted or of 6 distinct segments; outer segments herbaceous, spreading or re- 
flexed; inner segments larger than the outer, more or less colored, becoming enlarged and 
reticulate in fruit, often with cork swellings. Stamens 6: filaments very short. Style 
3-parted; stigma tufted, peltate. Fruit 3-angled, enclosed in the 3 inner perianth-seg- 
ments. (L. rumo==to suck; because the Romans sucked the leaves to allay thirst. ) 
A. Coarse plants, usually over 4 dm. high, not strongly sour; flowers not dioicous. 
B. Inner perianth-segments in fruit entire, or merely erose or undulate. 
C. None or only | 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 Pursh (Big-seed Dock) 
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. CR. confinis. ) 
R. occidentalis Wats. (Western Dock) 
FF. Leaves flat, lanceolate, rounded at base. E. 
R. hesperius Gr. 
EE. One inner perianth-segment in fruit with cork. E. 
R. patientia L. (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. CR. salicifolius. ) 
R. mexicanus Meisn. (Willow Dock) 
HH. Stems mostly not tufted, erect; leaves crisped at margin. W. E. 
R. crispus L. (Yellow Dock) 
GG. Inner perianth-segments in fruit scarcely 2 mm. wide: leaves somewhat 
crisped. W. R, conglomeratus Murr. (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 |—2 corks. 
J. Stems sparingly branched; often some of the lower leaves fiddle-shaped; in- 
ner perianth-segments with 10—20 teeth. W. 
= Re pulcher L. (Fiddle Dock) 
JJ. Stems branched at every joint; none of the leaves fiddle-shaped; inner 
perianth-segments with 6—1I0 teeth. W. E. 
R. obtusifolium L. (Bitter Dock) 
II. Annual; teeth of inner perianth-segments 4, longer than the segments are 
wide; fruit with 3 corks. W. C. 
R. persicarioides L. (Golden Dock) 
AA. Slender plants, 4 dm. or less high, very sour; flowers dioicous. 
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 Wats. (Mountain Dock) 
KK. Leaves hastate, oblanceolate; pedicels jointed at the summit; inner perianth- 
segments not winged in fruit; akene granular. W. C. E. (CR. acetosa for our re- 
gion. ) R. acetosella iDe Field Sorrel) 
