Platanthera L. C. M. Richard, 1817

D. M. Moore (ed.), 1980, CCIII Orchidaceae, Flora Europaea, Vol 5: Alismataceae to Orchidaceae, Camebridge: Cambridge University Press, pp. 325-350 : 331

13. Platanthera L. C. M. Richard 1

Stock usually with tubers. Leaves few, usually only the lowest 1 -3 well developed, the upper reduced to sheaths or with a small, bract-like lamina. Flowers white or green, in a usually fairly dense spike. Outer lateral perianth-segments patent, the inner lateral shorter, connivent with the outer median to form a galea. Labellum linear-oblong to rhombic-lanceolate, entire. Spur more or less cylindrical. Stigma single, flat; rostellum inconspicuous. Viscidia distinct; bursicles absent.

1 Spur 18-30 mm, longer than ovary

2 Anther-lobes parallel, almost contiguous; spur acute 1. bifolia

2 Anther-lobes convergent above, but widely separated below; spur somewhat dilated at apex 2. chlorantha

1 Spur 2-8 mm, shorter than ovary

3 Stem with 1 well-developed leaf; spike with 3-6 flowers 5. obtusata

3 Stem with at least 2 well-developed leaves; spike with numerous flowers

4 Lowest 2 leaves much larger than the others 3. micrantha

4 Lowest 2 leaves not contrasting markedly with the others, the second and third from the base being usually the largest 4. hyperborea