Keltalehdokki – Platanthera chlorantha

Perennial herb.

25–60 cm high.

The stem is erect and stout.

There are two nearly opposite leaves at the base of the stem. The basal leaves are 6–18 cm long. The lamina is simple, entire, oval and typically wider than the lamina of P. bifolia. There are 1–3 small and narrow hypsophylls higher up on the stem.

The root tubers are unbranched.

The inflorescence is a 5–20 cm long, rather dense, uniformly thick spike. The flower is bisexual, zygomorphic, yellowish greenish, odorless or weakly fragrant, and spurred. The spur is about 20 mm long, thickening towards the apex, thicker and more obtuse than the spur of P. bifolia. The upper part of the halves of anthers are close to each other and the lower parts of the halves of the anthers are further apart from each other. The labellum is about 10–16 mm long, narrow and simple.

The capsule is 12–15 mm long, erect, nearly appressed against the axis. The seeds are minuscule, dust-like.