Lathyrus palustris
Lathyrus tracyi
gesse des marais, marsh pea, marsh peavine, marsh vetchling
Tracy's pea, Tracy's sweet pea
narrowly to broadly winged, sprawling or climbing, basally branched 0–4 times, 2–10 dm.
angled, erect, sprawling, or climbing, often branched mid stem 1–4 times, 2–6 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.
2–6 cm;
tendrils absent to well developed, 0–3 cm, usually not branched;
stipules linear, 5–15 × 1–5 mm, much smaller than leaflets;
leaflets 4–8, often paired, blades ovate, 15–30 × 5–20 mm, surfaces glabrous, or linear, 30–70 × 1–10 mm, surfaces glabrous or pubescent.
2–7-flowered, 3–15 cm.
5–15-flowered, 2–7 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.
7–13 mm;
calyx lobes unequal, lateral lobes often linear-triangular, sometimes lanceolate, shorter than tube;
corolla white, banner erect, blade equal to claw, wings equal to keel;
ovary glabrous.
25–60 × 4–8 mm.
40–60 × 4–7 mm.
= 14.
= 14.
Lathyrus palustris
Lathyrus tracyi
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.)
Although W. L. Jepson (1909–1943, vol. 2) treated Lathyrus tracyi of northwestern California as a variety of L. bolanderi S. Watson (= L. vestitus), D. Isely (1992, 1998) considered L. tracyi a variety of L. lanszwertii. Lathyrus tracyi includes both ovate- and linear-leaflet forms. Linear-leaflet populations certainly suggest a relationship to L. lanszwertii, but ovate-leaflet forms, the presence of mid stem branching, and differences in floral structures suggest that L. tracyi may be better allied to L. holochlorus found to the north in the Willamette Valley of western Oregon and southwestern Washington. Lathyrus tracyi has been reported from Jackson County, Oregon, but specimens could not be examined.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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