DICOTYLEDONOUS PLANTS , 67 
reflexed at maturity. Calyx green, the valves broadly triangular, 
abruptly pointed, reticulated, a distinct long and narrow tubercle on 
the back of each. Swamps and wet ground.* 
3. R. crispus, L. YELLow Dock. Stout, smooth, 3-4 ft. high. 
Leaves lanceolate, margins very wavy, acute, the lower more or less 
heart-shaped. Root long, tapering gradually downward, yellow, 
very tough. Flowers in whorls crowded in long, straight, slender 
racemes. Valves roundish heart-shaped, mostly tubercled. A very 
hardy weed, introduced from Europe. 
Il. POLYGONUM, L. 
Annual or perennial, terrestrial or aquatic herbs, with 
enlarged joints and simple, alternate, entire leaves; the 
sheathing stipules often cut or fringed. Flowers perfect, 
usually white or rose-colored, each flower or cluster subtended 
by a membranaceous bract, similar to the stipules of the 
leaves. Calyx mostly 5-parted, the divisions petal-lke, erect 
and persistent. Stamens 3-9. Styles 2-3-parted. Fruit 
lens-shaped or 3-angled.* 
1. P. aviculare, L. Kwnot-Grass. Annual or perennial. Stem 
prostrate or ascending, diffuse, smooth, 6-24 in. long. Leaves small, 
lanceolate or linear-oblong, obtuse, nearly 
or quite sessile. Stipules thin and dry, 2—3- 
cleft or cut. Flower-clusters axillary, 1-5- 
flowered, flowers inconspicuous, nearly ses- 
sile. Calyx greenish-white, 5-parted, the 
lobes with white or colored borders. Stamens 
5-8. Style 3-parted; akene 3-angled, not 
shining. A common weed in dooryards and 
where the ground is trampled.* Fig, 10.— Buckwheat. 
2. P. Dumetorum, L. Fatse Buck- A, flower, longitudinal sec- 
WHEAT. Perennial ; stems slender, twining, eee nm idles ge = 
branched, 2-10 ft. long. Leaves ovate, ee 
taper-pointed, heart-shaped to halberd-shaped at the base, long- 
petioled. Stipules cylindrical, truncate. Flowers in axillary, more 
or less compound and leafy racemes. Calyx greenish-white, the 
outer lobes winged and forming a margin on the pedicel. Stamens 
8. Stigmas 3; akene 3-angled, black, smooth, and shining. Margins 
of fields and thickets.* 
