Lathyrus japonicus
Lathyrus palustris
beach or maritime or sand pea, beach pea, beach vetchling, maritime pea, sea pea, seaside pea
gesse des marais, marsh pea, marsh peavine, marsh vetchling
angled to narrowly winged, erect, sprawling, or climbing, basally branched 0–4 times, 1–10 dm.
narrowly to broadly winged, sprawling or climbing, basally branched 0–4 times, 2–10 dm.
3–15 cm;
tendrils usually well developed, branched or unbranched;
stipules sagittate-ovate, 7–35 × 7–30 mm, as large as basal leaflets;
leaflets 6–12, usually scattered, blades ovate to lanceolate, 15–55 × 5–35 mm, surfaces glabrous throughout or pubescent abaxially.
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.
4–9-flowered, 4–15 cm.
2–7-flowered, 3–15 cm.
12–29 mm;
calyx lobes unequal, lateral lobes linear-triangular, longer than tube;
corolla blue to purple, banner erect, blade longer than claw, wings equal to keel;
ovary eglandular and glandular-pubescent.
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.
35–65 × 6–12 mm.
25–60 × 4–8 mm.
= 14.
Lathyrus japonicus
Lathyrus palustris
Varieties 3 (3 in the flora).
Within Lathyrus japonicus, in the narrow sense, there is a south to north reduction in plant size, including plant height, robustness, and leaflet size, but not flower size, flower number, or fruit size. On the east coast of North America this shift seems fairly abrupt, giving the appearance of a clear distinction between var. maritimus and var. pellitus in the south, and var. japonicus to the north in Labrador and Greenland. However, on the West Coast, there are few truly pubescent forms (var. pellitus), and there seem to be many more intermediates between var. maritimus in the south and var. japonicus to the north.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
1. Stems 1–3.5 dm; leaflet blades 15–35 mm; tendrils unbranched, less than 3 cm. | var. japonicus |
1. Stems 3–10 dm; leaflet blades 30–50(–55) mm; tendrils branched, 3+ cm. | → 2 |
2. Leaflet blades glabrous. | var. maritimus |
2. Leaflet blades pubescent abaxially (especially new growth). | var. pellitus |
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
- Local floras: BC, CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW,
Go Botany, 
IL Wildflowers, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, PNW Herbaria - WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
