This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Lathyrus ochroleucus Hook. Fl. Bor. Am. 1: 159.
1833. Lathyrus glaucifolius Beck, Bot. 90. 1833.
Perennial, slender, glabrous and slightly glaucous; stem somewhat angled, climbing or trailing, 1°-2 1/2° long; stipules broad, folia-ceous, half-ovate and half-cordate, 8"-12" long; leaves petioled; leaflets 3-5 pairs, thin, pale beneath, ovate or broadly oval, acute or acutish at the apex, rounded at the base, 1-2' long; tendrils branched; peduncles shorter than the leaves; flowers 5-10 yellowish white, 7"-9" long; pod oblong-linear, sessile, glabrous, 1'-2' long.
Lathyrus pratensis L. Sp. PL 733. 1753.
Perennial, weak, slender, glabrous or sparingly pubescent, climbing or straggling, 1°-3° long. Stems angled, branching; stipules lan-olate, foliaceous, half-sagittate, acuminate, 6" - 12" long, nearly as large as the leaflets; leaves sessile; leaflets a single pair, oblong or linear-oblong, acute or acutish, mucronulate, 1'-1 1/2' long, 2"-4" wide; tendrils simple or branched; racemes exceeding the leaves; flowers 4-12, yellow, 6"-10" long; pods linear, glabrous, 1'-1 1/2' long.
In waste places, New Brunswick, New York, Massachusetts and Ontario. Also throughout Europe and in Russian Asia. Angleberries. Craw-peas. Mouse-pea. Tom Thumb. Yellow tar-fitch [tare vetch]. Lady's-fingers. June-Aug.
Lathyrus latifolius L. Sp. Pl. 733. 1753.
Perennial, glabrous; stems high-climbing, broadly winged, 30 long or more. Stipules lanceolate, acute, often 1' long; petioles as long as the stipules or longer, winged like the stem; leaflets a single pair, oblong-lanceolate to elliptic, strongly veined, 2-4' long, acute or mucronate; tendril branched; peduncles stout, curved, mostly longer than the leaves; flowers purple, racemose, purple to white, nearly 1' long.
Escaped from cultivation, Connecticut to District of Columbia. Native of Europe. Summer.
Lathyrus tuberòsus L., another perennial Old World species, with purple flowers, but with smaller thin leaflets and smaller flowers has been found in grassy places in Ontario, Vermont and eastern Massachusetts.
L. pusillus Ell. Bot. S. C. & Ga. 2: 223. 1823.
Annual, glabrous; stems usually branched near the base, spreading or climbing, narrowly 2-winged, 2° long or less. Leaflets a single pair, linear to linear-oblong, acute, 1/2'-2 1/2 long, with a filiform often 3-forked tendril between them; stipules lanceolate, slightly curved, auricled at the base, as long as the petiole or shorter; peduncles 2' long or less, 1-2-flowered; flowers purple, 2 1/2"-3 1/2' long, short-pedicelled; calyx-lobes narrowly lanceolate, acuminate, as long as the tube or somewhat longer; pods linear, 1'-1 1/2' long.