Rhododendron exuberans (Sleumer) Argent

J. Linn. Soc. Bot. 1982. 85: 12.

WFO ID: wfo-0000400828

IPNI ID: urn:lsid:ipni.org:names:911237-1

Verified by:

Description

Shrub to 4m. Twigs smooth, green, finely and sparsely scaly only; internodes 2–12cm. Leaves arranged in tight to loose pseudowhorls of 5–8 large and a few smaller. Blade 70–100 x 20–35mm, elliptic to broadly elliptic rarely somewhat obovate; apex acute, sometimes shortly acuminate; margin entire, flat but somewhat irregular; base tapering; obscurely scaly, the scales being very small and quickly disappearing from the upper side of the leaf. Scales sub-stellately lobed with small centres. Mid-vein distinct but smooth, hardly raised above or below; lateral veins 8–10 per side, issuing at an acute angle, very slightly impressed above. Petiole 3–5 x 2–3mm, very weakly grooved above, finely covered in scales. Flower buds (see p.327) to 35 x 15mm, narrowly ovoid, tapering to a very acute point; tips of the bracts only slightly spreading, glabrous, red. Inflorescence 1–3-flowered, an open umbel, the flowers half-hanging, orange becoming red with age, without scent. Pedicels 9 x 2mm, sparsely scaly and occasionally with a few simple hairs. Calyx a low ring, sparsely scaly. Corolla 25–38 x 25–35mm; tube c.20 x 11 x 19mm, straight, very sparsely and inconspicuously scaly outside, glabrous inside; lobes c.19 x 15mm, overlapping for c.½ their length. Stamens arranged all round the mouth of the flower, not exserted, slightly dimorphic; filaments c.15mm, glabrous or with scattered hairs at the base; anthers 5 x 2mm. Ovary 6 x 3mm, densely white-hairy and with a few scales; style c.12mm, glabrous; stigma c.2mm in diameter. Fruit 21 x 6mm, narrowly ellipsoidal. Seeds 5.2mm, without tails 0.8mm, the longest tail 2.6mm.

Distribution

Malaysia (Borneo), Sarawak, Mt Mulu, Mt Murud. Sabah, Mt Kinabalu (Marai-Parai), Mt Trus Madi, Mt Lumarku. Indonesia, W Kalimantan (Borneo), Mt Rajah.

Altitude

Habitat

Epiphytic in mossy forest

Nomenclatural History

R. nervulosum Sleumer var. exuberans Sleumer, Blumea 1963. 12: 113.

Notes

References

Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:271