Common name: Scented Onion Orchid
Microtis rara R.Br. APNI* 
Description: Slender terrestrial herb, 15–50 cm high.
Leaf 20–50 cm long.
Inflorescence to c. 50 cm high, 10–30-flowered; pedicels 1–2 mm long; bracts lanceolate, 3–4 mm long, 1–2 mm wide. Flowers fragrant, green, erect. Dorsal sepal ovate, 3–4 mm long, 1.5–2 mm wide, shallowly concave below, apex apiculate; lateral sepals linear to oblong, spreading, recurved or revolute, 2–3 mm long, 0.8 mm wide. Petals falcate to lanceolate, 2–2.5 mm long, 0.8 mm wide. Labellum ± oblong, usually constricted about middle, 3–4 mm long, 1–1.5 mm wide, margins crenulate, often thickened. Column incurved with prominent oblong to spathulate lateral appendages.
Flowering: October–January
Distribution and occurrence: Grows mostly in swamps or in forests in high-rainfall regions; chiefly in coastal district, west to the Blue Mtns.
NSW subdivisions: NC, CC, SC, CT, ST
Other Australian states: Qld Vic. Tas. W.A. S.A.
Microtis rara could be confused with M. unifolia but differs by its widely spaced flowers at maturity (versus closely spaced), the long-rectangular labellum 3-4 times longer than broad (versus 1.5-2 times longer than broad), and the prominant elliptical and domed apical labellum callus, which overlaps the labellum margin at the sinus apex (versus rounded apical labellum callus which is distant from the labellum margin).
Microtis rara could also be confused with M. oblonga, the two taxa share the oblong labellum and widely spaced flowers, but differ in the size and shape of the labellum apical callus. In Microtis rara the labellum apical callus is elliptic, and overlaps the labellum margin at the labellum sinus, whereas in M. oblonga (as provisionally accepted here) the labellum apical callus is rounded to cordate, and is well separated from the labellum margin. In herbarium material, care interpreting the degree of overlap between the callus and the labellum margin at the sinus apex is required, because the callus cells shrink when dry, and the whole callus is smaller than in life, and there may be a small separation between the labellum margin and the lower callus margin, however this is always much less than the separation in M. oblonga. The photograph of M. rara by Wendy Grimm (above), gives you a good idea of the size, shape, and prominance of the labellum apical callus in M. rara, it also illustrates well the flower spacing on the inflorescence.
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.
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