56 
POLYGONACEAE 
Leaves mostly narrow and lanceolate, jointed upon a short petiole. 
Perennial and more or less suffrutescent; flowers crowded at ends of 
branches.5. P. paronychia. 
Annual, prostrate ; flowers all along stem from the base.6. P. aviculare. 
1. P. amphibium L. Water Persicarta. Aquatic perennial; leaves 
floating, elliptical to oblong or oblong-lanceolate; spike terminal, ovate 
or oblong, 1.2 to 2.4 cm. long; calyx red; stamens 5; style 2-cleft.—Ponds 
and slow-flowing streams. 
2. P. muhlenbergii Wats. Perennial, aquatic or in half dry places; 
stems decumbent, 6 to 8.5 (or 17) dm. high; leaves thin; calyx rose-color 
or pink; style 2-cleft.—Lakes and sluggish streams. 
3. P. lapathifolium L. Common Knotweed. Annual; stems stout, 
branching, 3 to 11.5 dm. high; leaves broadly lanceolate, attenuate or long- 
acuminate ; sheathing stipules naked in age; racemes axillary and ter¬ 
minal, erect or nodding, 2.4 cm. long or more; calyx white or flesh-color; 
stamens 6; style 2 or 3-parted.—Borders of streams or in lowlands. 
4. P. acre H. B. K. Dotted Smartweed. Perennial, 5.8 to 14 dm. 
high; leaves lanceolate; sheathing stipules bristly ciliate; calyx greenish, 
conspicuously glandular; stamens 8; styles 2 or 3.—Low or marshy 
places. 
5. P. paronychia C. & S. Stems 3 to 8.5 dm. long, clothed below with 
old sheaths; leaves linear-lanceolate; sepals white or rose-color; stamens 
8, the three inner dilated at base.—Sand hills along the coast. 
6. P. aviculare L. Yard Grass. Annual; stems wiry, mostly pros¬ 
trate, often 5 to 10 dm. long, flowering from the base; leaves oblong, 
acute; calyx-lobes white with a green center; stamens 8; styles 3.—Nat. 
from Eur., common in hard, often beaten, soils. 
2. FAGOPYRUM Tourn. 
Annual herbs, similar to Polygonum. Leaves triangular-cordate or 
sagittate. Flowers white, in corymbose panicles. Stamens 8, as many 
honey glands alternating with the filaments. Styles 3. Achene acutely 
triangular, large. (Greek fagus, beech, and pyren, grain, the fruits re¬ 
sembling a beech nut.) 
1. F. esculentum Moench. Cultivated Buckwheat. Cult, from nor¬ 
thern Asia. The seeds are made into a flour which forms the basis of 
buckwheat cakes, one of the most delicious products of American cookery. 
3. RUMEX L. 
Coarse herbs with alternate and often large leaves. Flowers small, 
greenish or reddish, crowded and commonly whorled in panicled racemes. 
Sepals 6, the 3 outer spreading or reflexed in fruit, the 3 inner larger and 
somewhat colored, enlarging and closing over the nut-like fruit. Stamens 
6. Styles 3. (Old Latin name used by Pliny.) 
Flowers perfect or some staminate on the same plant; roots yellow, scented; 
pedicels jointed. 
Inner fruiting sepals entire (or nearly so) and 
Without callous grains; longer than broad.1. R. hymenosepalus. 
With callous grains. 
Leaves strongly undulate; fruiting sepal with a broad wing border¬ 
ing the callous grain.2. R. crisp us. 
Leaves slightly undulate or plane. 
