Australian Tropical Rainforest Plants - Online edition
Ipomoea velutina R.Br.
Brown, R. (1810) Prodromus Florae Novae Hollandiae : 485. Type: Northern Australia, R. Brown; (holo: BM?).
Velvety Morning Glory
A slender vine not exceeding a stem diameter of 2 cm.
Twigs and petioles may produce a small amount of milky exudate. Two pale, flat glands, one on each side, visible on the petiole just prior to its junction with the leaf blade. Leaf blades very variable in size, about 5-15 x 4-12 cm, petioles up to about 4 cm long. Both the upper and lower surfaces of the leaf blade densely clothed in pale or translucent hairs; stem and petioles similarly clothed.
Flowers about 5-6 cm diam. Calyx about 1 cm long. Corolla about 5 cm long, outer surface much paler than the inner. Staminal filaments about 15-17 mm long, bases clothed in erect, white hairs, anthers about 5 mm long. Pollen white, grains minutely spiny. Stigma white, two-lobed, sculptured like a cumulus cloud. Ovules two per locule.
Base of the style persistent at the apex of the fruit. Seeds +/- shaped like the segments of an orange (Citrus sinensis), each seed about 7-8 x 6 mm. Testa mainly glabrous except for a line of hairs along each of the outer angles of the seed. Endosperm intruding into the spaces between the two lobes of each cotyledon. Radicle somewhat swollen close to the apex.
Seed germination time 80 days. Cotyledons deeply bilobed at the apex, cotyledons about 30 x 38 mm, petioles about 30 mm long. Venation palmate, with five veins (including the midrib) radiating from the base. Midrib not reaching to the apex of the cotyledon. First pair of leaves ovate, apex obtuse, base truncate or obtuse. Upper and lower leaf blade surfaces minutely hairy, becoming glabrous. Hypocotyl absent. At the tenth leaf stage: leaf blade cordate, apex obtuse to retuse with a short, hairy, reflexed mucro, base auriculate. Lateral veins more closely spaced in the lower half of the leaf blade. Both the upper and lower surfaces clothed in translucent, mostly medifixed hairs. Midrib raised on the upper surface. 'Oil dots' visible with a lens when viewed from the upper surface and appear to occur in short lines. Taproot thick, carrot-like. Roots produce a copious clear exudate.
Endemic to Australia, occurs in NT and NEQ. Altitudinal range from near sea level (?) to 400 m. Grows in vine thicket and monsoon forest or on their margins.