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