Microtis atrata Lindl.

Yellow Onion-orchid

Edwards’s Bot. Reg. 25: Sketch Veg. Swan R., app. 54 (1840) APNI

Taxonomic status:Accepted

Occurrence status:Present

Establishment means:Native

Flowering stem 5–12(–25) cm tall, slender to stout. Leaf erect, 3–9 cm long, almost solid, yellowish green; sheath opening close to bottom of inflorescence.  Flowers 2–40, yellowish green, drying black, sometimes fragrant, minute, semi-erect, in dense spike 1–4 cm long; ovary obovoid, c. 2 mm long, sessile; dorsal sepal circular to ovate, c. 1 mm long, very obtuse, widely hooded; lateral sepals oblong, shorter than dorsal sepal but longer than petals, slightly concave, somewhat acute, spreading but not recurved; petals ovate, sickle-shaped, c. 0.5 mm long, concave, spreading below the dorsal sepal. Labellum reflexed, ovate to elliptic, 1–1.5 mm long; margins entire; apex obtuse; lamina with a dark green basal mound and often with 2–6 longitudinal rows of tiny papillae; calli absent. Column rugose and glandular. Flowers Sept.-Dec.

CVU, DunT, EGL, GipP, Glep, GGr, HSF, LoM, OtP, VVP, WaP, WPro, Wim. Also WA, SA, Tas. Found in swamps or soil that is boggy for part of the year, mainly in near-coastal areas.

Microtis atrata has the smallest flowers of any Australian terrestrial orchid. This feature, accompanied by the erect, almost solid leaf, the black colouration of dried plants, and the ovate to elliptic labellum without calli, distinguish it from all other species of Microtis.

The recent placement of this species into the monotypic genus Microtidium has not been generally accepted.

Created by: Jeff Jeanes, 2015-02-20
Updated by: Jeff Jeanes, 2015-02-20
Hero image
Distribution map
life Life
kingdom Plantae
phylum Tracheophyta
superorder Lilianae
order Asparagales
family Orchidaceae
genus Microtis
Higher taxa


Source: AVH (2014). Australia's Virtual Herbarium, Council of Heads of Australasian Herbaria, <http://avh.chah.org.au>. Find Microtis atrata in AVH ; Victorian Biodiversity Atlas, © The State of Victoria, Department of Environment and Primary Industries (published Dec. 2014) Find Microtis atrata in Victorian Biodiversity Atlas
  Bioregion Occurrence status Establishment means
Lowan Mallee present native
Wimmera present native
Glenelg Plain present native
Victorian Volcanic Plain present native
Gippsland Plain present native
Otway Plain present native
Warrnambool Plain present native
Central Victorian Uplands present native
Greater Grampians present native
Dundas Tablelands present native
East Gippsland Lowlands present native
Wilsons Promontory present native
Highlands-Southern Fall present native

State distribution

Distribution map
Western Australia
South Australia
New South Wales