Beach pea is a perennial, rhizomatous herbaceous species that is circumboreal in distribution. It is "widely distributed on coasts of temperate Asia, Europe, North America, and South America (Chile)" (Flora of China 2011). In North America, this includes the coastal areas of the Great Lakes. In British Columbia, it ranges along the Pacific coast from Vancouver to just north of Prince Rupert. This low growing, blue/pink/purple flowering species trails or climbs in well-drained sandy habitats proximal to the ocean (sandy coastal areas/foredunes), in dynamic drift areas or on stabilized foredunes. Leaves are alternate and pinnately compound with 6-10 leaflets, stems are not winged, and pods are hairy. Flowers are often two-coloured and are in racemes of 2-7.
Beach Pea is an ecologically and biogeographically interesting species. Plants are reported to flower in their third year, with pollination by long-tongued bumblebees (Low 2005). Seeds of this species disperse in sea water and may remain viable for up to 5 years, which may aid in long-distance dispersal (Wikipedia 2011).
A detailed description of this species is provided in the Flora of China online.
Perennial herb from a rhizome; stems trailing to climbing, 10-150 cm long, angled or flanged but not winged, glabrous to short-hairy.
Alternate, pinnately compound with 6 to 12 leaflets; leaflets paired or scattered, egg-shaped to oblong, 1-7 cm long, 0.5-4 cm wide, rather fleshy, strongly veined when dry; tendrils well developed, grasping or branched or neither; stipules large, leafy, obliquely arrowhead-shaped, about as long as the leaflets.
Inflorescence a loose, stalked, axillary cluster of 2 to 8 pea-like flowers; corollas reddish-purple to blue, often 2-coloured, up to 3 cm long, the wings and keel shorter than the banner, the banner-claw equal to the blade; calyces 10-15 mm long, the teeth lanceolate, the upper pair 1/2 as long as the lateral pair which are 1-2 mm shorter than the lowest one, all three of the lower teeth longer than the tube.
Pods, usually hairy, 3-7 cm long, 1 cm wide; seeds 5 to16.
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Synonyms and Alternate Names:
Lathyrus japonicus subsp. maritimus (L.) P.W. Ball
Lathyrus japonicus var. glaber (Ser.) Fernald
Lathyrus maritimus Bigelow
Lathyrus maritimus var. glaber (Ser.) Eames
Pisum maritimum L.
Pisum maritimum var. glabrum Ser.