PULSE FAMILY LEGUMINOSAE 
TRAILING WILD BEAN 
Strophostyles helvola (L.) Britton 
The Trailing Wild Bean is found throughout the eastern 
half of the United States. In Illinois it is common on sand 
ballast along railroads and on sandy shores of streams and ponds, 
and is found also in open woods where the 
soil is sandy. The blooming season is July 
to October, so that flowers and mature fruits 
may often be found together. 
This is a low twining or trailing annual 
vine that branches from the base and has 
stems 2-8 feet long. The leaflets may be 
either 3-lobed or entire and the lateral ones 
are often somewhat I-sided. 
The peduncles occur in the axils of the 
leaves and each bears 3-10 flowers in a cluster 
at the end. The greenish purple flowers are 
butterfly shaped, and the 5-toothed calyx has 
the 2 upper teeth a 
little shorter than the 
rest. The standard 
is nearly round and 
the 2 wing petals are 
oval or oblong. The 
long and slender keel 
mens and style. Fila- 
stamens are united 
is strongly incurved — 
and encloses the sta-_ 
ments of g of the 10 
and the other is free. The pistil develops into a nearly cylindrical, — 
slightly hairy, several-seeded pod. 
The Pink Wild Bean, Strophostyles umbellata (Muhl.) Britton, 
is a slender trailing perennial whose stems are clothed with back- 
ward pointing hairs. The unlobed leaflets are oblong, blunt and 
hairy on both sides. The pink flowers, one-half inch long, are 
on long peduncles in umbels that look like heads. The straight 
and slender pods are slightly flattened, about 2 inches long and 
somewhat hairy. The plant favors dry sandy ridges, knolls and 
dunes from Long Island to Illinois, south to Florida and Louisiana. 
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