Acianthus caudatus R.Br.

Mayfly Orchid

Prodr. 321 (1810) APNI

Taxonomic status:Accepted

Occurrence status:Present

Establishment means:Native

Flowering plant 6–14 cm tall. Leaf cordate to ovate, thin, 7–33 mm long, 7–30 mm wide, green above, reddish-purple beneath, margins bluntly toothed, sometimes minutely. Flowers 1–6, dark purplish, often with musty odour; pedicel (including ovary) 4–10 mm long, subtended by small bract; dorsal sepal more or less inflexed, 20–45 mm long, base concave, dilating narrowly above column, then tapering to long fine point; lateral sepals much shorter than dorsal sepal, 12–25 mm long, tapering to fine points curving upwards at tips; petals reflexed or spreading, curved-lanceolate, relatively short, c. 5 mm long. Labellum recurved or curved downwards in upper part, sessile, elongate-ovate to triangular, 4–6 mm long, c. 3 mm wide; base erect, embracing column, tip deflexed; margins entire; callus with 2 erect basal glands and a narrow longitudinal channel. Column with very narrow wings on underside of almost terete lower two-thirds. Flowers Aug.–Oct.

CVU, EGL, EGU, GipP, Glep, Gold, GGr, HNF, HSF, MuF, OtP, SnM, Strz, VRiv, VVP, WaP, WPro. Also SA, Qld, NSW, Tas. Scattered throughout southern Victoria, occurring in cool shaded positions in light forest but abundant only in sandy areas near-coast. An 1889 specimen from Boort represents the northernmost Victorian locality for the species and apparently it has not been collected from that vicinity since.

Source: Entwisle, T.J. (1994). Orchidaceae. In: Walsh, N.G.; Entwisle, T.J. (eds), Flora of Victoria Vol. 2, Ferns and Allied Plants, Conifers and Monocotyledons. Inkata Press, Melbourne.
Updated by: Jeff Jeanes, 2014-08-15
Hero image
Distribution map
life Life
kingdom Plantae
phylum Tracheophyta
superorder Lilianae
order Asparagales
family Orchidaceae
genus Acianthus
Higher taxa


Source: AVH (2014). Australia's Virtual Herbarium, Council of Heads of Australasian Herbaria, <>. Find Acianthus caudatus in AVH ; Victorian Biodiversity Atlas, © The State of Victoria, Department of Environment and Primary Industries (published Dec. 2014) Find Acianthus caudatus in Victorian Biodiversity Atlas
  Bioregion Occurrence status Establishment means
Glenelg Plain present native
Victorian Volcanic Plain present native
Victorian Riverina present native
Murray Fans present native
Gippsland Plain present native
Otway Plain present native
Warrnambool Plain present native
Goldfields present native
Central Victorian Uplands present native
Greater Grampians present native
East Gippsland Lowlands present native
East Gippsland Uplands present native
Wilsons Promontory present native
Highlands-Southern Fall present native
Highlands-Northern Fall present native
Strzelecki Ranges present native
Snowy Mountains present native

State distribution

Distribution map
South Australia
New South Wales