POLYGONACEAE 381 
rather sharply angled, the angles mostly armed with recurved prickles: leaf-blades linear 
or linear-lanceolate, subsagittate, 3-15 cm. long, acute or acutish, subsessile, cordate and 
more or less clasping, almost glabrous on the upper surface, glabrous beneath except the 
midrib which is sometimes sparsely pubescent with prickle-like hairs, glandular-ciliate : 
ocreae 1-2 cm. long, somewhat obliquely opened and spreading at the summit, naked, very 
thin, fringed around the base with small recurved prickles: inflorescence dichotomous, 
more or less compound, the ultimate divisions ending in clusters or spicate racemes : 
peduncles glandular: racemes few-flowered : ocreolae 1 mm. long, ciliate: calyx rose- 
colored, campanulate: sepals 2-3 mm. long, ovate-oblong, obtuse: stamens 5: achenes 
varying from broadly ovoid to obovoid, 3-angled, dark brown, smooth and shining, the 
angles obtuse. [Polygonum Beyrichianum Cham. & Schlecht. ] 
In low ground, Louisiana to Texas, Mexico and Brazil. Also in the West Indies. 
2. Tracaulon sagittatum (L.) Small. Annual, bright green or parts tinged with 
red. Stem decumbent, ascending or reclining, 3-15 dm. long, four-angled and finely chan- 
neled, armed on the angles with, sharp recurved prickles, by which the plant climbs: leaf- 
blades lanceolate or oblong, sagittate, 1-12 cm. long, cordate, the lower ones long-petioled, 
the upper short-petioled, lighter green beneath than above, slightly roughened on the edge 
by small prickles: ocreae funnelform, very oblique, 0.5-1 em. long, acute, eciliate : ocre- 
olae bract-like, lanceolate, 3-5 mm. long: calyx white, green or red, 4 mm. long : sepals 
oblong, obtuse : stamens 8: achenes 3-angled, 3-3.5 mm. long, ovoid, sharp-tipped, black 
or brownish, smooth and shining. [Polygonum sagittatum L.] 
In swamps, Newfoundland to Saskatchewan, Florida and Texas. 
3. Tracaulon arifólium (L.) Raf. Perennial or annual, bright green. Stem as- 
cending and reclining, 2-9 dm. long, nearly simple or much branched, armed on the four 
angles with stout recurved prickles, the peduncles and pedicels glandular or pubescent : 
leaf-blades broadly hastate, 2-18 em. long, cordate or subcordate, pubescent or glabrous on the 
lower surface, the basal lobes acuminate : ocreae funnelform, oblique, 0.5-1 em. long, fringed 
at the summit with short bristles and at the base with short bristle-like prickles: racemes 
1-2 em. long, somewhat leafy, interrupted : ocreolaefunnelform, oblique, 2 mm. long : calyx 
greenish or rose-colored : sepals 4, oblong, obtuse : stamens 8: achenes lenticular, 4 mm. 
long, obovoid or oblong-ovoid, dark brown or variegated, very smooth and shining. [ Poly- 
gonum arifolium L.] 
In swamps, New Brunswick to Minnesota and South Carolina. 
11. TINIARIA Reichenb. 
Annual or perennial often seurfy unarmed twining vines. Leaves alternate: blades 
membranous or leathery, cordate or hastate. Ocreae oblique, naked or fringed at the top 
or the base. Racemes loosely flowered, axillary or terminal, often paniculate, leafy- 
bracted or naked. Sepals 5, green, white or yellowish, 2 exterior, 2 interior and 1 with 
one edge interior and one edge exterior, this sepal and the two outer keeled or strongly 
and conspicuously winged.  Pedicels slender, reflexed and articulated. Stamens 8, in- 
cluded : filaments short, converging. Styles 3, short or almost wanting, distinct or rarely 
united. Achenes 3-angled, dark brown or black, included, smooth and shining or granu- 
lar and dull. Endosperm horny. Cotyledons accumbent. The plants flower in the sum- 
mer and fall. 
Outer sepals keeled at maturity. 
Inflorescence consisting mostly of axillary and terminal clusters and simple ra- 
cemes : achene granular. 1. T. Convolvulus. 
Inflorescence consisting mostly of axillary and terminal panicled racemes : achene : 
smooth 2. T. cilinodis. 
Outer sepals develo ing conspicuous wings 
Sepal-wings not ewes. ? 
Mature calyx 6-8 mm. long ; wings flat. 3. T. dumetorum. 
Mature calyx 10-12 mm. long ; wings crisped. 4. T. scandens. 
Sepal-wings incised. 5. T. cristata. 
1. Tiniaria Gonvólvulus (L.) Webb. & Moq. Annual, scurfy, dull green or pale 
green. Stem prostrate or twining, 1-12 dm. long, branched from near the base, the inter- 
nodes of the older branches greatly elongating: leaf-blades broadly or narrowly ovate or 
ovate-sagittate, the uppermost nearly sagittate, 1.5-6 em. long, acuminate at the apex, cor- 
date or truncate at the base, somewhat undulate and crisped : ocreae oblique, 2-4 mm. long, 
acute, rough on the edges: flowers several in a cluster: racemes simple, 1-6 cm. long, 
loosely flowered, interrupted : calyx green, at length 3.5-4 mm. long, closely investing the 
fruit: sepals oblong, obtuse, the three outer ones keeled : stamens 8: achenes 3-angled, 
