Acianthus saxatilis D.L.Jones & M.A.Clem.

Plant: Glabrous, terrestrial, tuberous herb growing in small colonies.

Stem: Stem erect to slightly bent forward, widest and darkest green at base, 40-90 mm tall, 1.5-3 mm thick.

Leaf: Porrect, cordate, 38-70 x 20-90 mm, light green above, reddish green to light greenish purple beneath, entire; veins not prominent; apex attenuate to acuminate.

Inflorescence: Raceme erect, 3-8 cm tall, slender, thinner than the stem, 1-5[-8]-flowered.

Floral Bracts: Prominent, cordate, 4-12 x 4-13 mm, light green, foliose.

Ovary: Linear, 8-10 x 1-2 mm, curved, light green.

Flowers: Largest for the genus, porrect, 10-13 x 5-7 mm, light green with faint light brown margins on sepals; labellum light greenish-brown to greenish-yellow with light brown margins, brown callus and darker brown apex.

Dorsal Sepal: Ovate-lanceolate, 8-12 x 4.5-8 mm, cucullate, acute to apiculate.

Lateral Sepals: Connate at the very base then free, projected obliquely forwards below the labellum and forming a flat to slightly concave platform- like structure; each sepal asymmetrically oblanceolate, 9.5-14 x 3-3.5 mm, narrowed to the base.

Petals: Porrect to upswept, partially hidden by the dorsal sepal, obliquely lanceolate, falcate, 7-9 x c. 3 mm, acuminate.

Labellum: Sessile, obliquely porrect, 8.5-10 x 4.5-5 mm, elliptical to elliptical lanceolate, cymbiforme, thickest in basal half, flat to shallowly concave; margins entire or distally irregular; apex acute to subacute or apiculate. Callus consisting of paired basal glands and a narrow brownish central band; glands mostly hidden, tonsil-like, each 1.5-2 mm long; central band c. 1 mm wide, restricted to proximal two-thirds of labellum.

Column: Erect, 4.5-6.5 mm long, shallowly curved, green. Anther 0.6-0.8 mm long, rounded, with light brown band, without a rostrum. Stigma elliptical, c. 0.7-0.8 mm wide. Pollinarium c. 0.8 mm wide, consisting of two hemipollinaria, each comprised of a small hemivisidium and four poillinia in two unequal pairs; viscidium c. 0.2 mm wide; pollinia clavoid, light yellow, the smaller four c. 0.35 mm long, the larger four c. 0.5 mm long.

Capsules: Ellipsoid, 10-12 x c. 3 mm.

Type: Queensland; Lightning Falls, Lamington National Park, 12 Feb. 2010, M.T. Mathieson MTM0606, L.Rintoul and M.Pears (holo BRI! AQ792112)