Common name: Common Onion Orchid
Microtis unifolia (G.Forst.) Rchb.f. APNI*
Synonyms: Microtis porrifolia (Sw.) R.Br. ex Spreng. APNI*
Microtis aemula Schltdl. APNI*
Description: Slender to robust terrestrial herb, usually 20–60 cm high.
Leaf 8–60 cm long.
Inflorescence to 60 cm high, 6–100-flowered; pedicels 1–1.5 mm long; bract lanceolate to ± ovate, 2–4 mm long, 1–1.5 mm wide. Flowers often lightly scented, green or yellow-green, ± erect. Dorsal sepal ovate to circular, 2–4 mm long, 1–2 mm wide, markedly concave below, apex broad and obtuse to acute, often apiculate. Lateral sepals linear to oblong to lanceolate or ovate, recurved or rolled, 1.5–2.5 mm long by 0.8–1.2 mm wide. Petals ± falcate to lanceolate or ovate, 1.4–1.8 long, 0.4–0.8 mm wide. Labellum oblong, 1.2–2.5 mm long, 0.4–2 mm wide, basal calli saddle-shaped, rounded or square, smooth; margins undulate, crenulate to rugulose. Column erect or decurved, with ovate lateral appendages.
Distribution and occurrence: Grows in wide variety of habitats from coastal swamps to rock outcrops in semi-arid areas; west to Deniliquin district.
NSW subdivisions: NC, CC, SC, NT, CT, ST, NWS, CWS, SWS, NWP, SWP, LHI
Other Australian states: Qld Vic. Tas. W.A. S.A.
Microtis unifolia can be recognised by the combination of parallel-sided, rectangular labellum around 2 times longer than broad, whose margins are crenulate due to the presence of projecting and bulging marginal cells, usually undulate in the lower third, and whose apex is shallowly notched at most.
Microtis unifolia could be confused with M. arenaria but differs by the labellum apex being shallowly notched at most (not deeply notched); the labellum sides are parallel and the labellum does not flare slightly toward the apex (not flaring slightly); and the labellum apical callus never overlaps the labellum margin at the apex of the notch in the labellum apex (may be overlapping in M. arenaria).
The separation ofMicrotis unifoliafrom M. angusii is challenging, the most reliable character seems to be the labellum shape, which tapers in M. angusii, but see comments on the M. angusii PlantNet page.
Text by R. R. Rowe, updated by Matt A.M. Renner (5 November 2020).
Taxon concept: Flora of NSW 4 (1993)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.