Melodinus acutiflorus F.Muell.

Apocynaceae

Mueller, F.J.H. von (1857) Transactions of the Philosophical Institute of Victoria 2: 71. Type: Queensland, Brisbane River, Hill 27; holo: MEL.

Byamurra; White Flowered Melodinus; Melodinus, White Flowered; Merangarra

Vine stem diameters to 3 cm recorded. Pith produces a small amount of milky exudate, bark produces little if any exudate.

Twigs and petioles produce a milky exudate. Leaf blades elliptic to ovate, about 7.5-19 x 3-7.5 cm, petioles about 0.2-0.8 cm long. Lateral veins about 15-18 on each side of the midrib. A raised line usually visible on the twigs between the petiole bases.

Flowers about 15-20 mm diam. on a pedicel about 13 mm long. Bracts present on the pedicel, one bract just beneath the flower. Sepals about 2 mm long. Corolla tube about 8 mm long, lobes about 10 mm long. Inner surface of the corolla tube hairy, mainly in the area surrounding the anthers. Anthers about 2 mm long, filaments about 0.5 mm long. Ovary about 5 mm long. Style expanded to form a style head resembling a crows nest on a mast.

Fruits globose, about 5-6 cm diam., calyx persistent at the base. Cut or damaged fruit produces a copious milky exudate. Fruit appears to ripen from the apex down to the base, the apex often being orange while the base is green. Seeds numerous in each fruit, seeds irregular in shape, about 8-10 mm long. Testa somewhat wrinkled and marked by scroll-like lines. Endosperm ruminate with testa intrusions. Embryo about 8 mm long, cotyledons much wider than the radicle but of similar length.

Cotyledons about 8-13 x 2-4 mm, broadly lanceolate to elliptic. First pair of leaves elliptic, apex acuminate, base cuneate. Lateral veins forming loops inside the blade margin, midrib raised on the upper surface. At the tenth leaf stage: seedling completely glabrous, leaf blade elliptic, apex acuminate, base cuneate; midrib raised on the upper surface. Intramarginal vein difficult to see between the leaf blade margin and the looping lateral veins. Small stipule-like glands about 0.5 mm long present on the stems close to the point of attachment of the petioles. Seed germination time 77 days.

Occurs in NEQ, rarely collected in CEQ, and south eastern Queensland and southwards as far as Port Macquarie in New South Wales. Altitudinal range in NEQ from near sea level to 1200 m. Grows in a variety of well developed rain forest types.

Melodinus guilfoylei F.Muell., Fragmenta Phytographiae Australiae 6: 118(1868), Type: Qld, Rockingham Bay, 13-14 February 1867, J. Dallachy: lecto: MEL; iso: BRI. Fide Forster (1992). Melodinus gratus S.Moore, The Journal of Botany 55 : 306(1917), Type: Kuranda, in forest, 1000 ft., 1914; n. 6349. [L.S.Gibbs]. Holo: BM, iso: NSW. Melodinus australis Maiden & Betche, Proceedings of the Linnean Society of New South Wales 24(1): 647(1900), Type: Between Unkya Creek and Allgomera, Yarrahappini Mountain, Kempsey District (G.R. Brown, January, 1897 & November, 1899), lecto