210 CHENOPODIACEAE 
but leaves broad triangular with depression at base. Margin of wings 
of seed hull irregularly notched. Shady woods, New York and southward. 
28. P. sagittatum, L. (Fig. 11, pl. 34.) ARRow-LEAvVED TEAR 
THUMB. Stem slender, 4-angled, the plant reclining upon other plants 
and clinging to them by recurved prickles. Leaves narrow arrow-head- 
form, heart-shaped at base; leaf-stalk short. Wet or moist soil; com- 
mon. 
29. P. arifolium, L. (Fig. 3, pl. 34.) /HaLBerp-LEAvVED TEAR 
THuMB. Stem 4-angled, armed with recurved prickles, climbing by these. 
Leaves broad egg-shaped with spreading wings at base, on long leaf- 
stalks, Flowers few in an elongated cluster. Moist soil. Common. 
4. OXYRIA, Hill. 
A few alpine species with round kidney-form leaves on long leaf- 
stalks mostly from the root. Flowers on a scape arising from the base, 
small, greenish, clustered in a rather loose narrow and elongated group 
(raceme). Calyx of 4 divisions; stamens 8; fruit a thin, flattened, lens- 
shaped body extending beyond the calyx and surrounded by a broad wing. 
O. digyna, Hill. Mounrarin Sorrer. High regions of the White 
Mountains and far north and west. July-Sept. 
5. POLYGONELLA, Michx. 
Herbs with branched conspicuously jointed stems and narrow leaves. 
Flowers on jointed flower stems. Calyx 5-parted, colored. The 3 inner 
segments investing the fruit and becoming larger than the others and 
often developing wings at the angles. Stamens 8; style 3-parted. Fruit 
a 3-angled dry nut similar to the fruit of Polygonum. 
P. articulata, (L.) Meisn. (Fig. 1, pl. 34.) Coast JOINTWEED. 
Plant 4 to 15 in. high; stem wiry, slender, branching. Leaves linear. 
Flowers in slender diffuse clusters on flower stalks closely jointed. 
Flowers very small, rose color. Sandy coasts and inland sandy places. 
Order IV.—CHENOPODIINEAE. The Order of the Pig- 
weeds 
Herbaceous plants, some with fleshy stems and leaves. Leaves 
alternate (except in Salicornia, in our region), smooth or covered 
with hairs. The. flowers are, in general, small, inconspicuous, 
green, crowded in glomerate masses or in spikes, but sometimes 
solitary and moderately conspicuous, while in one instance the 
glomerate masses are brightly colored. Among the Amaranths 
some species have colored bracts. In some families the flowers 
are perfect, having the stamens and pistils in the same envelope; 
in other families the stamens and pistils occupy different flowers 
and sometimes different plants. The corolla is always wanting; 
calyx generally divided in 5 parts, but in Salicornia and some 
