[riz-an-thel-ler]
Terrestrial saprophytic herbs, unique in Australia, possibly entirely subterranean. Rhizomes short, thickened, without roots, branching. Inflorescences erect, subsessile, solitary, terminal; those on the smaller lateral rhizomes with well developed bracteate stems. flower-heads surrounded by rather large ovate bracts.

R. Gardneri, Roger; after C. A. Gardner. Flower-heads up to 2 in. in diameter, cup-like, bracts whitish, ovate or oblong-lanceolate, up to 2 in. long, over-lapping. Flowers numerous, small, sessile, dark purple, crowded. Sepals and petals erect, dorsal sepal hooded, lateral sepals very fleshy, widely triangular. Petals oblong-falcate, acute, membraneous, slightly shorter and much narrower than the sepals, forming a galea with the dorsal sepal. Lip reddish, attached to the apex of column-foot by a delicate movable claw, tongue-like, very large in comparison to size of flower. Column erect. (Described Journal Royal Society W.A., Vol. XV., October, 1928.)
W.A.: Corrigin, Shackleton, Goomaling. May - June.

The discovery of this orchid at Corrigin by Mr. John Trott when cultivating virgin soil previously rolled and burned, aroused interest among Australian orchidologists. Note by Dr. Rogers, to whom specimens were forwarded for identification:
"A superficial examination of the single capitulum which first reached me, suggested that it belonged to a member of the Glomerinae, a group of orchids chiefly restricted to the Malaysian and Papuasian areas. Further examination, how-ever, showed that there were tribal differences, and that like so many Australian orchids, the new plant was neottious in character. It had indeed distinct affinities with the Gastrodiineae, a subtribe in which it is now usual to include Gastrodia, R. Br., Didymoplexis, Griff., Leucolena, Ridl., and Auxopas, Scltr. The first two genera are represented in our own flora, the others are respectively endemic to the Malay Peninsula and Cameroons. Of these four, it is undoubtedly the most closely related to Gastrodia, R. Br. From this, how-ever, it differs in the remarkable inflorescence of numerous sessile flowers, united by their ovaries and crowded together in a bracteate capitulum; also in its unwinged column, and in its stigma which is situated on the face of the column near the apex, and not at the base as in Gastrodia, and likewise by its slenderly clawed, very movable and exceedingly fleshy labellum. Some of these differences appear to be of sufficient importance to warrant its exclusion from the Gastrodiinae. I must therefore regard it as the type of a new sub-tribe, belonging to the Polychondreae. The records, as shown by the material available, indicate extreme stress of environment followed by the most abject plant poverty and degradation."