Lesser Butterfly-orchid and Greater Butterfly-orchid

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Lesser Butterfly Orchid

Platanthera bifolia

  • Written also: Lesser Butterfly-orchid
  • Family: Orchid Family – Orchidaceae
  • Growing form: Perennial herb. Root tubers unbranched.
  • Height: 25–50 cm (10–20 in.).
  • Flower: Perianth irregular (zygomorphic), white, approx. 1.5–2 cm (0.6–0.8 in.) wide. Tepals 6, in 2 whorls, upper outside tepal helmet-like, one inner tepal elaborated into labellum. Labellum under perianth, spurred, approx. 12–14 mm (0.48–0.56 in.) long, almost linear, narrow, lime green. Spur 25–40 mm (1–1.6 in.) long, thin, with tapered tip. Androecium and gynoecium fused into a column, stamens 1, pollinia close to each other, stigmas 2. Inflorescence a quite lax, uniformly thick spike. Flower fragrant especially at night.
  • Leaves: Basal leaves 2, almost opposite, stalked. Blade obovate–elliptic, with entire margin, glabrous. 1–3 small linear upper leaves alternate on upper stem.
  • Fruit: Erect, almost parallel with stem, round, strongly veined capsule. Seeds tiny, like dust.
  • Habitat: Quite rich forest heaths, broad-leaved ridged forests, grove-like forests, rich mixed swamps, meadows.
  • Flowering time: June(–July).
  • Endangerment: Protected in all of Finland except the Åland Islands.

Lesser butterfly orchid is the third most common orchid that grows in Finland, which in no way makes it any less attractive: its beautiful inflorescence and strong scent have made it one of our best known orchids. According to an old legend Jesus was praying the night before his crucifixion and a group of angels came down to comfort him, placing themselves in lesser butterfly orchid’s flowers. In memory of that the lesser butterfly orchid’s flower is still in the shape of an angel, shining white in the twilight on summer nights and emitting a strong, pleasant scent. Apart from humans, its scent also attracts night butterflies, mainly hawk moths but also geometrid and owlet moths. The viscidia on lesser butterfly orchid’s column are almost closed together and stick tightly around the butterfly’s proboscis. The airborne pollinia dry out and bend forwards within a few minutes. During that time the hawk moth empties one plant of its nectar and flies towards another, where the pollinia will make direct contact with the stigma and ensure pollination.

Greater butterfly orchid (P. chlorantha), which grows on the Åland Islands, is highly reminiscent of lesser butterfly orchid. The easiest way to tell it apart is perhaps by its greenish yellow flowers, but the most important differences are in the fragrance and the position of the pollinia. Greater butterfly orchid’s flowers don’t smell of anything much at all to the human nose, and their pollinia are widely branched, pointing away from each other. These two small differences – the fragrance and the distance between the viscidia – make them unsuited to certain pollinators and suffice to distinguish between the two species.

Other species from the same genus
Other species from the same family

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