Ponerorchis graminifolia

Ponerorchis graminifolia is a short herbaceous perennial growing from an ovoid tuber. It reaches a height of 10–15 cm (less often 25 cm). It has two to four linear leaves, 7–15 cm long. The inflorescence is a raceme containing 2–15 flowers. Each flower is about 15 mm across, pink to purplish overall. The upper sepal and the lateral petals form a "helmet". The lip or labellum is about 13 mm long, deeply divided into three broad lobes. A spur is present, 10–15 mm long, shorter than the ovary.[2]

Several varieties have been described, some of which vary in flower colour. P. graminifolia var. kurokamiana has reddish purple flowers; P. graminifolia var. nigropunctata has paler flowers with darker spots or spotted lines.[2]

Ponerorchis graminifolia was first described in 1852, by Heinrich Gustav Reichenbach; it is the type species of the genus Ponerorchis.[1] The genus name is derived from the Greek πονηρός, meaning "wretched", "worthless", "useless".[2] The specific epithet graminifolia means "grass-leaved".[3]

As of March 2018, four varieties have been recognized:[4][2]

• Ponerorchis graminifolia var. graminifolia – Japan and Korea
• Ponerorchis graminifolia var. kurokamiana (Hatus. & Ohwi) T.Hashim. – Japan; only up to 10 cm tall; reddish purple flowers
• Ponerorchis graminifolia var. nigropunctata F.Maek. ex K.Inoue (as var. micropunctata in some sources) – Japan; up to 25 cm tall; flowers paler with darker spots
• Ponerorchis graminifolia var. suzukiana (Ohwi) Soó – Japan; more and larger leaves (4–6); pale reddish purple flowers

Ponerorchis graminifolia is native to south Korea and south-central and south Japan (Honshu, Shikoku and Kyushu).[1][2] It grows in mountainous areas, particularly among damp rocks.[2]

Ponerorchis graminifolia is cultivated as an ornamental plant, particularly in Japan, where many cultivars of uchou-ran have been described with widely differing flower colours and markings, from pure white to darkish purple, with or without spots and markings. In Britain, they can be grown in pots in a gritty compost. Without forcing, they then come into growth in early spring, flower in late spring and early summer, dying down before the autumn, after which they are kept dry and frost-free over winter. Propagation is via tuber division or seed.[2][5]

Hybrids with Ponerorchis chidorii and Ponerorchis gracilis (Amitostigma gracile) have been reported to be in cultivation.[2]