Australian Tropical Rainforest Plants - Online edition

Marsdenia straminea P.I.Forst.


Vine
Click/tap on images to enlarge
Flowers and flower buds. © CSIRO
Flowers. © CSIRO
Leaves and Flowers. © CSIRO
Leaves and fruits. © CSIRO
Scale bar 10mm. © CSIRO
Scale bar 10mm. © CSIRO
Cotyledon stage, epigeal germination. © CSIRO
10th leaf stage. © CSIRO
Vine stem bark and vine stem transverse section. © CSIRO
Family

Forster, P.I. (1995) Australian Systematic Botany 8(5): 816. Type: Queensland, State Forest Reserve 191 (17 20S, 145 30E), B. Gray 20062V, 6 Nov. 1978; holo: QRS; iso: BRI.

Stem

Vine stem diameters to 10 cm recorded. Dead bark layered, showing growth rings in transverse section. Sections of included bark occur in the wood and radiate from the centre like the spokes of a badly deformed wheel.

Leaves

Twigs, petioles and leaves produce a milky exudate. Leaf blades about 5.5-11.5 x 2.5-7 cm, petioles about 0.6-3 cm long, grooved on the upper surface. Underside of the leaf blade densely clothed in pale hairs. Twigs and petioles densely clothed in pale brown hairs. Stipules not obvious but twigs marked by scars which extend from the base of one petiole to the other. A few colleters (small finger-like glands) present on the upper surface of the midrib near its junction with the petiole.

Flowers

Flowers borne in umbel-like inflorescences or compressed racemes. Anthers ending in a pale (white or cream-coloured) obtuse or rounded papery appendage. Pollen in comparatively large hyaline (honey-coloured) lumps. Structures which could be interpreted as staminodes present between the corolla lobes. Stigma large, almost spherical.

Fruit

Fruits narrowly obclavate, about 80-95 x 6-7 mm. Seeds about 10-12 mm. Plume about 30-36 mm long. Embryo about 10-12 mm long, cotyledons about 8 mm long, radicle about 2 mm long, cotyledons wider than the radicle.

Seedlings

Cotyledons about 22-27 x 10-13 mm, venation more conspicuous on the lower surface. Petioles and midrib clothed in hairs. Hypocotyl clothed in hairs. First pair of leaves elliptical, apex bluntly pointed, base cuneate, both the upper and lower surfaces clothed in hairs. At the tenth leaf stage: all plant parts clothed in translucent or pale-coloured hairs. Leaf blade elliptic, apex acuminate, base cuneate-obtuse. Midrib hairy, raised in a groove on the upper surface. Lateral veins about 6-7 on each side of the midrib Colleters about 8 per leaf blade. Minute stipule-like glands about 0.5 mm long present between the points of attachment of the petioles. Lower part of the stem swollen, fissured and somewhat corky. Seed germination time 18 days.

Distribution and Ecology

Endemic to NEQ. Altitudinal range not known, all collections made at 750 m. Grows in well developed upland rain forest on basalt. An uncommon and rarely collected species.

RFK Code
2046
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