Common name: Underground Orchid
Rhizanthella slateri (Rupp) M.A.Clem. & Cribb APNI*
Description: Terrestrial saprophytic herb with fleshy underground stem to 15 cm long and 15 mm diam., whitish, often branching, with prominent, fleshy, overlapping bracts; stems branching, 1–4 flowering heads, the heads maturing below the soil surface or extending almost 20 mm above the ground.
Flowering heads to c. 20 mm diam., the receptacle of up to 18, whitish triangular bracts to 8 mm long; flowers up to 30, tubular and purplish, sepals and petals free.
Dorsal sepal curved, the tip narrowing linear to filiform, the base broad and hooding the column and most of the 2 lateral petals; lateral sepals erect, broad at base but each lateral sepal folding lengthwise into a filiform tip longer than the dorsal sepal and often protruding beyond the length of bracts making up the cup. Lateral petals about half the length of the lateral sepals. Labellum claw a short, flexible hinge; labellum lamina cordate, thick, tongue-like with the upper surface covered with fine papillae. Column short and broad with column wings reduced to narrow, papillose 'ears;' anther broad and curving, stigma a thickened pad.
Distribution and occurrence: Grows in sclerophyll forest in shallow to deep loams. Collections tend to be accidental and it is not possible to determine distribution accurately; recorded for the Blue Mtns, also Bulahdelah south to Dharug N.P.
NSW subdivisions: NC, CC, ?SC, CT
Other Australian states: Qld
Threatened species: NSW BCA: Vulnerable; Commonwealth EPBC: Endangered
This species was previously placed in its own genus, Cryptanthemis.
Text by P. H. Weston
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.