Small-white Orchid Pseudorchis-albida: identification, distribution, pictures

This so-called boreal (of northern forest regions) orchid is classified as vulnerable in Britain, where it has a mainly northerly distribution. In its southerly sites in England, Wales and Ireland, its numbers have declined steeply (and from many former sites it has disappeared altogether). Small White-orchid is tolerant of both alkaline and mildly acidic habitats and can be found growing in rough pastures, poor grasslands, roadside verges and hay meadows. Pseudorchis albida can be confused with three other rare species: Creeping Lady's-tresses Goodyera repens, Irish Lady's tresses Spiranthes romanzoffiana, and Dense-flowered Orchid Neotinea maculata although there are slight variations in the flowering times of each. The flowering time of Small White-orchid depends upon how far north it is growing and also its altitude; however, generally speaking the flowers appear from late May until mid-July. On mainland Europe this plant is found in scattered locations from Russia in the north as far south as Crete; it is most abundant in Iceland, the Faroes and parts of Scandinavia.

Distribution Map		Key Features
	Records for the Small White-orchid from BSBI are shown on the map with most recent in front. (Hover the mouse over the small map to expand it.) CLICK HERE to visit the BSBI website page for updated data and maps with separated data for individual record periods.	Plant: usually under 20cm in height but occasionally up to 40cm; stem mid-green and slightly angled towards the tip; 2 or 3 brown or whitish sheaths situated at the base. Leaves: 4 to 6 shiny green, oval leaves sheathing the lower stem with 1 or 2 smaller bract-like leaves above. Bracts: green with pointed tips. Flowers: up to 70 held in a densely-packed cylindrical inflorescence which sometimes has a rather one-sided appearance. The individual flowers are very small and pale with sepals that are white-to-cream and petals and lip washed greenish to yellowish. The lip is broad and blunt with three distinct lobes. The flowers have a faintly vanilla-like scent.

Image Gallery for Small-white Orchid Pseudorchis-albida

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Title of album Description of album
Title of album Description of album

Pollination

Taxonomy & Hybrids

No specific information is available, but the flowers produce nectar which rewards butterflies and day-flying moths as well as bees. Some self-pollination also occurs.

The specific name albida means 'white'.

Small White-orchid is divided into two subspecies of which Pseudorchis albida (the nominate species) in found in Britain and in lowland and northern parts of Europe. The subspecies straminea has larger and yellower flowers and is found in the mountain regions of Central Europe. The latter is sometimes regarded as a separate species, Pseudorchis straminea.

The plants found in Britain are divided into two varieties: var. albida is found on more acidic soils and has lateral lobes of the lip clearly shorter than the central one; var. tricuspis grows in alkaline conditions and, as the scientific name suggests, has three more equally sized lobes than those of var. albida.

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