BUCKWHEAT FAMILY 



30. Polygonum Douglasii Greene. 

 Douglas' Knot weed. (Fig. 1347.) 



/Wr;'""'"" Douglasii 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, S'-iS' tall, simple 

 or usually much branched, almost terete. 

 Leaves oblong or narrowly lanceolate, %'-i' 

 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 8; style 3-partcd; 

 achene 3-angled, i / '4' // -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-Svpt. 



Polygonum Convolvulus 



Black Bindweed. (Fig. 1348.) 



Polygonum Omrolvulus I.. Sp. PI. 364. 1753. 



Annual, glabrous, scurfy, stem twining or trail- 

 ing, 6 / -3 long, mostly branched, the internode* 

 elongated. Leaves ovate-sagittate or the upper- 

 most lanceolate-sagittate, long-petioletl, acuminate 

 at the apex, slightly ciliate, li'-j' 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, olx>void-pyram- 

 idal, \}z" long, thick-pointed, black, granular, 

 rather dull. 



In waste and cultivated grounds, nearly throughout 

 North America except the 1 1 dized 



from Europe. Native of Asia. Sotnetitm-- a trouble- 

 some weed. Calyx rarely 6-parted. July-Sept. 



32. Polygonum cilinode Michx. 

 Fringed Black Bindweed. (Fig. 1349.) 



P. cilinode Michx.. Fl. Bor. Am. i: 241. 1803. 



Perennial, sparingly pubescent, stem red or 

 reddish, twining or prostrate, i-io long. 

 Leaves broadly ovate or somewhat hastate, acu- 

 minate at the apex, cordate at the base, rather 

 long-petioled, undulate, finely ciliate, i'-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; acheue 3-angled, oblong-pyramidal or 

 ovoid.nearly i^" long, very smooth and shining. 



In rocky places, Nova Scotia to Ontario. Minm- 

 sota and Pennsylvania, south in the Alleghaniei to 

 North Carolina. Ascends to 2000 ft. in the Catskills. 

 June-Sept. 



