Rhaphidospora platyphylla (S.Moore) Bremek. ex A.R.Bean

Acanthaceae

Bean, A.R. (2017) Austrobaileya 10(1): 85.

Perennial tuberous herb to shrub, straggling or upright to about 1 m tall. Stems constricted above leaf nodes, longitudinally ribbed, glabrous or with eglandular hairs, and conspicuous cigar-shaped cystoliths (deposits of calcium carbonate) visible with a lens.

Leaves variable, lower leaves larger and on long petioles usually thinly winged to the base, leaves gradually reducing in size up the stems, and upper leaves on short petioles or +/- sessile, mostly glabrous or with white eglandular hairs. Leaf blades ovate, rhomboid to cordate, about 6-225 mm x 2.5-96 mm, petioles about 0-50 mm long though usually thinly winged to base, mostly glabrous or with  sparse white hairs. Leaf base attenuate on large leaves to attentuate, rounded or caudate on smaller leaves; leaf apex acuminate to acute; margins crenate. Cigar-shaped cystoliths (deposits of calcium carbonate) visible with a lens on both surfaces but more onscure beneath. Midrib with a double ridge on the upper surface at least towards the base of the leaf blade. Lateral veins raised on the upper surface of the leaf blade. Pith rather copious.

Inflorescences axillary and terminal, usually a many-flowered dichotomously branched panicle often with a central axis, and axillary and young inflorescences appear as more simple 2-3-few-flowered dichotomously branched panicles. Peduncles with glandular and eglandular hairs. Bracts and bracteoles ca. 1.2-1.8 mm long. Calyx with 5 linear lobes, with glandular and eglandular hairs. Corolla tube 5-6 mm long, upper lip 2.7-3.5 mm long, lower lip with median lobe 4 mm long, lateral lobes 5.5 mm long; corolla outside hairy, inside glabrous. Stamens 2, filaments with a line of hairs otherwise glabrous, anthers lopsided and staggered, hairs present, the lower anther locule with a basal appendage to ca. 0.3 mm long. Ovary seated on a conspicuous disk, hairy. Style long and slender, stigma small and terminal.

Capsules +/- clavate, ca. 12 mm long, lower half constricted into narrow stalk, widened above into seed-bearing portion ca. 4.5 mm wide, hairy on the outer surface. Seeds light brown, flattened, ca. 2.8 mm diameter, up to four per capsule; testa clothed in pale brown spines. Radicle curved along the side of the cotyledons.

Features not available.

Occurs in CYP and in NEQ. In CYP recorded from the Pascoe River south, and in NEQ as far south as Black Mountain south of Cooktown. Altitudinal range from sea level to 400 m. Usually grows in semi-deciduous vine thickets, monsoon forest and gallery forest. Also occurs in New Guinea.

Description adapted from Barker (1996) J.Adel.Bot.Gard. Vol. 17: 151, and specimens at the Australian Tropical Herbarium.

Justicia platyphylla S.Moore, Journal of Botany, British and Foreign 58: 193 (1920). Type: "Papua New Guinea. CENTRAL PROVINCE: Astrolabe Range, 1 August 1918, C.T. White 270 (holo: BM, image seen; iso: BRI)."