About Lathyrus pratensis L.
Lathyrus pratensis L., commonly known as meadow vetchling, is a perennial herb. It has a limp, unwinged, erect, hairy stem that reaches 25 to 60 cm (10 to 24 in) in height. Its leaves grow in an alternate arrangement, with short stalks and large stipules. Leaf blades are pinnate, consisting of a single pair of broad lanceolate leaflets that have blunt tips and entire margins, ending in a terminal unbranched tendril.
The inflorescence has a long stem and bears a cluster of five to twelve yellow flowers. Each individual flower measures 10 to 16 mm (0.4 to 0.6 in) long, with five sepals, five irregularly arranged petals, ten stamens, and a single carpel. The petals have specialized forms: the uppermost petal is called the "standard", the two lateral petals are called "wings", and the lowest two petals are joined together to form the "keel". After flowering, the plant produces a long black fruit pod. Meadow vetchling flowers between June and August.
This species is native to Europe and Asia, and has been introduced to other regions across the globe. In the United States, it occurs primarily in the northwestern states of Oregon and Alaska. Its typical habitat includes rough grassy areas, broad-leaved woodland, forest margins, hedgerows, and banks, where it uses its tendrils to clamber over surrounding other vegetation.
