Australian Tropical Rainforest Plants - Online edition

Rhododendron viriosum Craven


Epiphyte
Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Leaves and flowers. © CSIRO
Flowers. © CSIRO
Scale bar 10mm. © CSIRO
10th leaf stage. © CSIRO
Cotyledon stage, epigeal germination. © CSIRO
Family

Craven, L.A. (2002) Edinburgh Journal of Botany 59(3): 448-450. Type: cultivated in the Australian National Botanic Gardens at Canberra, 22 ii 1994, Craven 9354 (holo. CANB; iso. A, B, BRI, E, L, MEL, QRS). (Provenance: Queensland: Mount Windsor Tableland, 27 v 1989, Jones & Clements 4420 (CANB).

Common name

Rhododendron; Rhododendron, Native; Native Rhododendron

Stem

Usually grows as a terrestrial, lithophytic or epiphytic shrub.

Leaves

Leaves in pseudowhorls of 2-6. Leaf blades rather thick and leathery, about 2.5-11 x 1-7 cm, cracking when folded. Apex acuminate to obtuse. Lateral veins 4-9 on each side of midrib, form loops inside the blade margin. Underside of the leaf blade marked by numerous dark peltate scales. Petiole channelled on the upper surface.

Flowers

Umbel 2-7-flowered. Corolla funnel-shaped, straight, red to reddish-pink, 3.5-5 cm long in all, sparsely hairy outside and marked by scales. Stamens ten, anthers presented around the throat (more or less in a cicle, absent or rarely present in the upper part of the throat), anthers red; filaments red, hairy. Base of the ovary surrounded by a lobed disk with the staminal filaments inserted in the indentations. Pollen white. Ovary with scales, with dense white hairs. Basal half of the style clothed in scales and white hairs. Stigma 4-lobed.

Fruit

Capsule rather long and narrow before dehiscing, about 1.5-3 cm long. Seed narrow, about 3-4 mm long with a slender somewhat twisted wing or tail on each end. Embryo cylindrical, cotyledons about as wide as the radicle. Seeds may germinate inside the capsule.

Seedlings

Seed germination time 23 to 331 days. Cotyledons obovate, ovate to elliptic, about 1.5-3 x 0.5-1 mm. First pair of true leaves obovate, about 2-3 x 1 mm, apex obtuse, base cuneate, glabrous, petiole about 1 mm long, lateral veins not visible. At the tenth leaf stage: all seedling parts clothed in pale brown scale-like glands which are visible to the naked eye. Leaf blade elliptic-obovate, about 8 x 5 mm, apex obtuse, midrib depressed on the upper surface. Lateral veins difficult to distinguish. Terminal bud scaly.

Distribution and Ecology

Endemic to NEQ, occurs on Mt Lewis, Mt Spurgeon, Pinnacle Rock, the Windsor Tableland, Mt Finnigan, Mt Pieter Botte and Thornton Peak. Altitudinal range from 940-1330 m. Grows as an epiphyte in well developed rain forest but also found as a lithophytic shrub on boulders in stunted windswept rain forest on mountain tops.

RFK Code

3656

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