[The Genus Lathyrus in the Columbia River Gorge of Oregon and Washington]

Grass Pea, Grass Peavine

Lathyrus sphaericus

Stem leaves and flower of Grass Pea, Grass Peavine: Lathyrus sphaericus

The photo above shows the upper stem of grass pea as seen about 7 miles northeast of Roseburg, OR..........late June 2005. Note the the long, thin paired leaflets and angled stem as well as the bristle at the upper base of the pedicel.

Banner of Grass Pea, Grass Peavine: Lathyrus sphaericusThe photo at right shows a close-up of the banner of grass pea as seen about 7 miles northeast of Roseburg, OR..........late June 2005. Note the lighter colored keel.
Characteristics:

Grass pea is a weedy annual with one to several glabrous stems arising from 20-50 cm high. Plants climb through foliage using their tendrils but are not vining. The stems range from wingless to very narrowly winged. The stipules are bilobed and linear to linear-lanceolate in shape, the upper lobe measuring about twice as long as the lower lobe. The stipules are about 1/4-1/3 the length of the leaflets. The leaves are arranged alternately along the stem and consist of 2 linear, linear-lanceolate or narrowly elliptic leaflets from 3-6 cm long. The lower leaves are tipped with a short bristle while the upper leaves are tipped with simple to branched tendrils.

The single flower is found at the end of long peduncle (1-2,5 cm long) which ends in a straight to curved bristle at the base of the pedicel. The calyx is 5-8 mm long with linear-lanceolate teeth which range from equal to twice as long as the calyx tube. The corolla ranges from reddish to bluish-purple and measures 1 cm long. The glabrous pods are straight and measure 4-5 cm long and about 3-4 mm wide.


Habitat:

Grass pea may be found in disturbed locations such as along roads, waste areas, gravel quarries and fallow fields.


Range:

A Eurasian species, grass pea may generally be found west of the Cascade Mt. crest in the Willamette and Umpqua Valleys of Oregon.

In the Columbia River Gorge, it may be found between the elevations of 100'-400' from near Wind Mt. eastward to near the Klickitat River.


Sideview of the calyx and corolla of Grass Pea, Grass Peavine: Lathyrus sphaericus

The photo above shows a light purple-flowered grass pea as seen at Catherine Creek, central Columbia River Gorge.........May 14, 2006.

Sideview of the calyx and corolla of Grass Pea, Grass Peavine: Lathyrus sphaericus

The photo above shows a good close-up side view of the calyx and corolla of grass pea. Note the bristle at the upper base of the pedicel as well as the erect banner. Note also the calyx teeth which are shorter than to nearly equal in length to the calyx tube.

Seed pod of Grass Pea, Grass Peavine: Lathyrus sphaericus

A close-up of the pod of grass pea.

Stem leaves, flower and stipules of Grass Pea, Grass Peavine: Lathyrus sphaericus - Stipules of Grass Pea, Grass Peavine: Lathyrus sphaericus

The photo above left shows the upper stem, paired leaflets and flower of grass pea as seen at Catherine Creek, central Columbia River Gorge. The long, thin stipules at the base of the flower and leaf may be seen in this view..........May 14, 2006. The photo right shows the narrow stipules of grass pea from the same location and date.

Sideview of the calyx and corolla of Grass Pea, Grass Peavine: Lathyrus sphaericus

Close-up sideview of the calyx and corolla of grass pea as seen at Catherine Creek, Columbia River Gorge........June 3, 2009.

Paul Slichter