Hoya sussuela (Roxb.) Merr.

Apocynaceae

Merrill, E.D. (1917) Interpret. Rumph. Herb. Amboinense : 438.

A slender vine not exceeding a stem diameter of 2 cm.

Twigs, petioles and leaves produce a milky exudate. Leaf blades thick and fleshy, about 6-9 x 2.5-4.5 cm, petioles about 1-1.5 cm long. Usually 2 colleters (small or relatively large finger-like glands) present on the upper surface of the midrib close to its junction with the petiole.

Inflorescence not strictly axillary as it arises from the twig between the petiole bases. Inflorescence an umbelliform raceme. Peduncles about 10-30 mm long. Pedicels about 20-25 mm long, producing a milky exudate when broken. Calyx lobes about 3 mm long. Small cream or yellow glands visible on the inner surface of the calyx one at the junction of each pair of adjacent sepals. Corolla stiff and leathery, about 45 mm diam. at maturity. Inner surface clothed in short hairs or tubercles. Anthers almost horizontal, sessile, fused to form a structure surrounding the style and stigma. Pollen aggregated in pollinia.

Fruits about 14-20 x 4 cm. Seeds numerous, each seed about 8 x 2.5-3 mm. Plumes about 25-70 mm long, attached to the narrower end of the seed. Endosperm scanty. Cotyledons about 4.5 mm long. Radicle about 3 mm long. Cotyledons wider than the radicle.

Cotyledons elliptic, about 12 x 6-7 mm, petioles clothed in curved hairs. First pair of leaves ovate to elliptic, apex acute, base obtuse, upper surface of the leaf blade almost glabrous, lower surface and the margins clothed in hairs. At the tenth leaf stage: leaf blade thick and fleshy, elliptic to ovate, apex acuminate, base cordate, almost peltate, midrib depressed on the upper surface. Upper and lower leaf blade surfaces sparsely hairy. Terminal bud and stem densely clothed in short curly hairs. Seed germination time 6 days.

Occurs in CYP. Altitudinal range from near sea level to 200 m. Grows in monsoon forest and rain forest. Also occurs in New Guinea and other parts of Malesia.

Hoya lauterbachii K.Schum., Monatsschrift fur Kakteenkunde 6(1) : 7(1896), Type: New Guinea: im Walde am Mittellauf des Gogol Flusses, 10 November 1890, C. Lauterbach; holo: B. Asclepias sussuela Roxb., Fl. Ind. ed. 2, 2 : 31(1832), Type: Corona Ariodnes. Rumph. Herb. Amboinense 5: t. 172 (1750).