Description

Shrub or small tree to 6m. Twigs 3–5mm in diameter, rounded, smooth, green or reddish, covered in flat brown scales; internodes 3–12cm. Leaves spirally arranged or weakly arranged in very loose pseudowhorls. Blade 110–160 x 30–50mm, narrowly elliptic; apex acutely pointed; margin entire and flat but strongly rolled back in young expanding leaves; base tapering, often shortly truncate, glabrescent and indistinctly dark punctate above, laxly and persistently scaly beneath. Scales minute, shallowly lobed to sub-circular with a broad marginal zone and small centre, weakly impressed. Mid-vein slightly raised above proximally but then becoming slightly impressed, raised below throughout its length; lateral veins numerous, slender, smooth or slightly raised in dried specimens, reticulation obscure when fresh, dense, fine, but prominent on both sides when dry. Petiole 10–20 x 4–5mm, not grooved, green or red, scaly. Flower buds ovoid, to 30 x 15mm. Outer bracts to 30 x 12mm, ovate, inner ones broadly ovate-oblong, innermost spathulate, obtuse, membranous, all glabrous apart from sparse marginal scales. Bracteoles c.20 x 1mm, linear, glabrous. Inflorescence 4–7-flowered in an open umbel, the flowers held horizontally. Pedicels 22–32 x 2mm, red or green, sparsely scaly, not hairy. Calyx 4–5mm in diameter, obliquely disc-shaped, the margin wavy and indistinctly 5-lobed, glabrous. Corolla 30–64 x 35–75mm, clear yellow or yellow flushed with orange, usually strongly and sweetly scented; tube 14–34 x 8 x 20mm, funnel-shaped, straight, with a few scattered scales outside, densely short-hairy inside proximally; lobes 20–37 x 21–36mm, broadly obovate to sub-circular, half-spreading, overlapping up to ¾. Stamens loosely and irregularly arranged on the lower side of the flower, sometimes in two groups on each side, exserted up to 10mm; filaments c.35mm, hairy in the lower 1⁄3; anthers 4–5 x 1mm, yellow or purple, curved, minutely apiculate. Disc thick and prominent, glabrous, or occasionally shortly hairy at the upper margin. Ovary 8–10 x 2–3mm, cylindrical, tapering gradually distally, appearing glabrous, but laxly finely and very shortly hairy and with some sparse scales; style 20–25mm, glabrous or slightly (and minutely) hairy at the very base; stigma c.5mm in diameter, yellow or turning red with age. Fruit 52 x 9mm, cylindrical but tapering at each end. Seeds 5mm, without tails 1mm, the longest tail 2mm.

Distribution

Malaysia (Borneo), Sabah, Mt Kinabalu and Mt Alab (Crocker Range).

Altitude

Habitat

Usually growing terrestrially in shaded moist valleys often in the ultrabasic zone on Mt Kinabalu.

Nomenclatural History

Notes

References

Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:274