BUCKWHEAT FAMILY. 563 
24. Polygonum Rayi Babingt. Ray’s Knotweed. (Fig. 1341.) 
Polygonum Rayi Babingt. Man. Brit. Bot. Ed. 2, 
275. 1848. 
Perennial or annual, glabrous, slightly glau- 
cous, stem 3/-24’ long, prostrate, usually much 
branched, striate. Leaves ovate-lanceolate or 
oblong, 3/’-15’ long, short-petioled, acute or 
obtusish at the apex, veined beneath, incon- 
spicuously so above, shorter than the internodes, 
inconspicuously jointed to the ocreae; ocreae 
2-parted, becoming lacerate, silvery, brown and 
glaucous at the base when old; flowers 2-4 to- 
gether in the axils; stamens 5 or 6; style short, 
3-parted to the base; achene ovoid, 3-angled, 
2/’-3’’ long, slightly granular but shining, much 
exceeding the calyx. 
In waste places, New Brunswick and Prince Ed- 
ward Island to British Columbia, south along the 
Atlantic Coast to Virginia. Naturalized from 
Europe? May-Sept. 
25. Polygonum eréctum [L. Erect 
Knotweed. (Fig. 1342.) 
Polygonum erectum I,. Sp. Pl. 363. 1753. 
Annual, glabrous, stem erect or ascending, 8/-2° 
high, terete, nearly simple or much _ branched. 
Leaves oval, oblong or obovate, subsessile or 
short-petioled, 3//-18’’ long, obtuse or subacute at 
the apex, conspicuously jointed to the ocreae; 
ocreae oblique, funnelform, soon lacerate, silvery 
when young; flowers 1-2 together in the axils; 
calyx greenish, enlarged in fruit; stamens 6 (some- 
times 5) style very short, 3-parted to near the 
base; achene ovoid-pyramidal, 3-angled, 134// 
long, reticulated and dull, invested by the calyx, 
or the apex slightly protruding. 
In moist or dry soil, Ontario to the Northwest Ter- 
ritory, Tennessee and Arkansas. July—Sept. 
26. Polygonum exsértum Small. Long- 
fruited Knotweed. (Fig. 1343.) 
P. exsertum Small, Bull. Torr. Club, 21: 172. 1894. 
Annual, glabrous, sometimes slightly glaucous, 
stem slender, brownish, erect or nearly so, con- 
spicuously striate, branched, 114°-3° tall. Leaves 
lanceolate, rarely oblanceolate, %4/’-114’ long, acute 
or cuspidate at the apex, acuminate at the base, 
nearly sessile; ocreae 2-4-parted when young, soon 
lacerate, silvery, becoming brownish; calyx green- 
ish, or white, 6-parted to near the base; stamens 5 
or 6, included; style 3-cleft or 3-parted, very short; 
achene 3-angled, narrowly pyramidal, 214//-3// 
long, more or less constricted above the middle, 
chestnut-brown, smooth, shining, 2-3 times as long 
as the calyx, at length twisted. 
Northwest Territory, south to Illinois, Missouri 
and Nebraska and on the Atlantic coast, in brackish 
marshes, from Maine to New York. Aug.-—Oct. 
