BUCKWHEAT FAMILY. 565 
30. Polygonum Douglasii Greene. 
Douglas’ Knotweed. (Fig. 1347-) 
Polygonum Douglasti Greene, Bull. Cal. Acad. 
(II.) 1: 125. 1885. 
Annual, similar to the preceding species, gla- 
brous, somewhat rough at the nodes, sometimes 
slightly glaucous, stem erect, 8/18’ tall, simple 
or usually much branched, almost terete. 
Leaves oblong or narrowly lanceolate, 14’—2’ 
long, subsessile, rather thin, flat or revolute, 
with no lateral impressions parallel to the mid- 
rib; ocreae oblique, short, soon lacerate; clus- 
ters axillary, several-flowered; the flowers and 
fruit deflexed; calyx green with white or rose- 
colored margin; stamens §; style 3-parted; 
achene 3-angled, 11¢’’-2’’ long, oblong or ovoid- 
oblong, black, smooth and shining. 
Northwest Territory and British Columbia to New 
Mexico and Indian Territory, east through Ontario 
to northern New York and Vermont. June-Sept. 
31. Polygonum Convolvulus L. Black Bindweed. (Fig. 1348.) 
Polygonum Convolvulus V,. Sp. Pl. 364. 1753- 
Annual, glabrous, scurfy, stem twining or trail- 
ing, 6’-3° long, mostly branched, the internodes 
elongated. Leaves ovate-sagittate or the upper- 
most lanceolate-sagittate, long-petioled, acuminate 
at the apex, slightly ciliate, %4/—3/ long; ocreae ob- 
lique, short, rough on the margin; axillary clusters 
or racemes loosely flowered; flowers greenish, pen- 
dulous on slender pedicels; calyx 5-parted, closely 
investing the achene, the outer lobes slightly or 
not at all keeled; stamens 8; style short, nearly 
entire; stigmas 3; achene 3-angled, obovoid-pyram- 
idal, 114’ long, thick-pointed, black, granular, 
rather dull. 
In waste and cultivated grounds, nearly throughout 
North America except the extreme north. Naturalized 
from Europe. Native of Asia. Sometimes a trouble- 
some weed. Calyx rarely 6-parted. July—Sept. 
32. Polygonum cilindde Michx. 
Fringed Black Bindweed. (Fig. 1349.) 
P. cilinode Michx. F1. Bor. Am, 1: 241. 1803. 
Perennial, sparingly pubescent, stem red or 
reddish, twining or prostrate, 1°-10° long. 
Leaves broadly ovate or somewhat hastate, acu- 
thinate at the apex, cordate at the base, rather 
long-petioled, undulate, finely ciliate, 1/-4/ 
long, or the upper smaller; ocreae small, armed 
with reflexed bristles near the base; racemes 
mostly panicled, axillary and terminal, inter- 
rupted; calyx whitish; style short, 3-parted to 
the base; achene 3-angled, oblong-pyramidal or 
ovoid,nearly 114’ long, very smooth and shining. 
In rocky places, Nova Scotia to Ontario, Minne 
sota and Pennsylvania, south in the Alleghanies to 
North Carolina. Ascends to 2000 ft. in the Catskills. 
June—Sept. 
