Lathyrus palustris
Lathyrus brownii
gesse des marais, marsh pea, marsh peavine, marsh vetchling
Brown's brush pea, Brown's pea, Brown's sweet pea
narrowly to broadly winged, sprawling or climbing, basally branched 0–4 times, 2–10 dm.
angled, sprawling, basally branched 0–3 times, 2–5 dm.
1–6 cm;
tendrils well developed;
stipules ovate-lanceolate to linear, 5–25 × 1–10 mm, much smaller than leaflets;
leaflets 4–8, paired, blades lanceolate to linear, 15–75 × 2–20 mm, surfaces glabrous, glabrate, or pubescent.
4–6 cm;
tendrils well developed;
stipules linear, 5–15 × 1–5 mm, much smaller than leaflets;
leaflets 6–10, scattered, blades ovate to linear, 15–40 × 1–10 mm, surfaces glabrous.
2–7-flowered, 3–15 cm.
2–4-flowered, 3–4 cm.
10–15 mm;
calyx lobes unequal, lateral lobes deltate, shorter than tube;
corolla blue-purple, banner erect, blade equal to claw, wings equal to keel;
ovary glandular-pubescent.
12–16 mm;
calyx lobes unequal, lateral lobes deltate, shorter than tube;
corolla purple, banner erect, blade longer than claw, wings longer than keel (by 1–3 mm);
ovary glabrous.
25–60 × 4–8 mm.
30–40 × 5–8 mm.
= 14.
Lathyrus palustris
Lathyrus brownii
Morphological variation within Lathyrus palustris is extensive. Although the most distinctive forms (see synonyms) have been accorded formal nomenclatural recognition (M. L. Fernald 1911; C. L. Hitchcock 1952), intergradation among these mostly sympatric ecotypes is widespread (D. Isely 1998). In Nunavut, it is known only from Akimiski Island in James Bay.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Lathyrus brownii has been variously allied with L. pauciflorus (C. L. Hitchcock 1952) or with L. lanszwertii (R. C. Barneby 1989). It is distinct from L. pauciflorus by its smaller leaflets and flowers and by its range (northeastern California and adjacent Nevada and Oregon versus Colorado and Utah to Idaho, northeastern Oregon, and eastern Washington), and from L. lanszwertii by its larger flowers, smaller leaflets, general absence of pubescence, and its more typical prostrate, sprawling habit.
C. L. Hitchcock (1952) considered Lathyrus schaffneri Rydberg as described by L. Abrams and R. S. Ferris (1923–1960, vol. 2) to be referable to L. brownii.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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