Electronic Flora of South Australia
Electronic Flora of South Australia
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Electronic Flora of South Australia species Fact Sheet

Family: Orchidaceae
Microtis atrata

Citation: Lindley, Sketch Veg. Swan Riv. Col. liv (1840).

Synonymy: M. minutiflora F. Muell., Fragm. Phyt. Aust. 1:90 (1858). , Microtidium atratum, Microtis atrata

Common name: Yellow onion-orchid.

A minute species, 3-9 cm high, rarely drawn up to 20 cm when growing in water; leaf-fistula close to the inflorescence, lamina exceeding the latter in length; the whole of the living plant including the flowers a yellowish-green colour but drying black.

Flowers semi-erect, 2-40, very minute, sometimes fragrant, in a somewhat dense spike 1-3 cm long; ovary ovoid, c. 2 x c. 1.5 mm, sessile; dorsal sepal orbicular to ovate, 1.2-1.5 mm long and wide, very obtuse, widely galeate; lateral sepals oblong, c. 0.8 x c. 0.2 mm, slightly concave, subacute, spreading but not recurveal; petals ovate-falcate, c. 0.6 x c. 0.2 mm, concave, spreading below the dorsal sepal; labellum ovate to elliptic, c. 0.8-1 x c. 0.6 mm, spreading or reflexed; apex rounded, obtuse; margins entire; lamina often with 2-6 longitudinal lines, minutely tuberculate, no callosities; column c. 0.6 mm high, rather rugose and glandular; anther hemispherical; pollinia connected directly to a viscid disk; no caudicle; stigma semilunar; rostellum showing as a dark-green dot in the upper border.

Published illustration: Curtis (1980) Student's flora of Tasmania 4A:pl. 8; Hoffman & Brown (1984) Orchids of south-west Australia, p. 234.

Distribution:  Forms small dense colonies in boggy soil or around swamp margins in high rainfall districts; uncommon.

S.Aust.: EP, SL, KI, SE.   W.Aust.; Vic.; Tas.

Conservation status: native

Flowering time: Oct. — Dec.

SA Distribution Map based
on current data relating to
specimens held in the
State Herbarium of South Australia

Biology: No text

Author: Not yet available

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