Lesser butterfly-orchids are distinguished by their two shining green basal leaves, especially of the hill form, which are shorter and broader and by the angle of the pollinia.

The upper sepal and petals form a loose triangular hood above the pollinia, which lie parallel and close together, obscuring the opening into the spur, which is long and almost straight.

The flowers are night-scented, but the chemical components of the scent are different from those of greater butterfly-orchid and attract different pollinators.

They are found in grasslands, woodlands (especially beech woods in southern England), in hill pastures up to 400m, on heaths and moorland, and in tussocky marshy ground.

Sphingid moths are attracted by the scent of this orchid, and tend to hover in front of the flowers, resting their forelegs on the lip.