Aquatic and Wetland Vascular Plants of the Northern Great Plains
28. Fabaceae, the Bean Family
4. Lathyrus L. -- Vetchling
1. Lathyrus palustris L. -- Marsh vetchling
Rhizomatous, climbing perennial, clinging to surrounding vegetation by tendrils;
stems strongly 2-winged, 3-10 dm long. Leaves pinnately compound,
5-10 cm long, the terminal leaflet modified as a tendril, otherwise leaflets
in 2-4 pairs, linear to lanceolate, occasionally elliptic, 2-7 cm long, 3-25
mm wide, apiculate; stipules prominent, semisagittate, 1-3 cm long. Flowers
in lateral racemes, 2-6 per raceme, reddish-purple, rarely whitish, drying blue
to blue-violet; calyx irregular, 7-10 mm long, the lowest lobe considerably
longer than the others; corolla 12-20 mm long; stamens diadelphous
in a 9 + 1 arrangement; style bearded along the inner side. Fruits
resembling a pea pod, flat, dehiscent, many-seeded, 3.5-5 cm long. Jun--Aug.
Wet meadows, stream banks and boggy or swampy places; occasional in e and nc
ND, e SD and e NE; (Circumboreal, in N.Amer. s to NJ, OH, IN, MO, NE, CO and
CA).