Th. d'altonii Rog. Trant. R.S.S.A., 54, 1930, 42

Up to 15 cm. high. Leaf up to 9 cm. long, expanded at the base, then abruptly constricted into a narrow-linear blade, spirally coiled so as to encircle the stem. Flowers 1–2, dark purple with darker striae, perianth segments up to 14 mm. long. Column erect, purplish at the base, merging to yellow at the top. Midlobe absent, lateral lobes primary (often connected at the back with a series of small calli), oblong-falcate, obtuse, simple, erect, as high as the anther, bright yellow. Anther connective protruding conspicuously.

Distribution. Australia—occasional throughout Victoria. New Zealand—2. (North Auckland), Kaitaia, 11.1908–24, R. H. and H. B. Matthews.

Flowers Oct.–Nov., sea-level—1,000 ft.; rather rare; related to and probably derived from the Westralian Th. variegata Ldl. The description has been adapted from Cheeseman's original and carefully compared with Matthew's photographs of the living plant and with dried specimens from both sides of the Tasman. Lectotype in Herb. Cheeseman, in the Auckland Museum. Lake Tangonge, 9.1911. H. B. Matthews. Sheet No. 25890.