Description

Shrub to 3m. Twigs smooth, finely longitudinally striated when dry and with scattered dark-brown scales; internodes 5–12cm. Leaves 3–5 together in tight pseudowhorls. Blade 40–80 x 23–37mm, elliptic, narrowly ovate or obovate; apex broadly acute, obtuse or rounded; margin entire, slightly revolute; base broadly tapering to rounded; laxly silvery scaly but quickly glabrescent and dark green above, persistently laxly scaly and paler below. Scales rounded, variable in size, with a broad marginal flange and small centre. Mid-vein distinct, above broad at the base and longitudinally grooved but quickly tapering to a narrow, impressed channel, green; broad and strongly raised throughout its length below, deep reddish-purple; lateral veins 7–9 per side, issuing at an angle of 45–90°, strongly impressed above, almost to the leaf edge, giving a rugose surface, very prominent and red in colour below. Petiole 8–12 x 3–4mm, red, weakly grooved above, scaly. Flower buds to c.20 x 10mm, glossy dark purplish-red, elliptic. Bracts ovate, often with a dark purple median line, the tips of the bracts broadly pointed and reflexed to c.4mm, these tips scaly both inside and out. Inflorescence a 6–10-flowered open or one-sided umbel, the flowers semi-erect to horizontal, white, or pale pink, fragrant. Pedicels red, 12–26 x c.2mm, minutely rough with scales and short simple hairs. Calyx a low lobed scaly and hairy ring, 1–1.5mm high. Corolla 40–46 x 35–45mm; tube 35–40 x 9 x 5mm, straight, covered in scales outside, densely short-hairy inside near the base; lobes 18 x 14–18mm, slightly forward pointing or spreading to the perpendicular, overlapping to c.halfway, slightly scaly outside. Stamens irregular in length, included c.2mm below the mouth; filaments white or pale pink, tapering slightly distally, hairy throughout their length; anthers c.2.8 x 1.25mm, brown with a finely granular surface and oblique pores. Disc lobed, with short erect hairs. Ovary 5.5 x 3.5mm, ovoid to almost conical, tapering slightly towards both base and apex, densely scaly and covered in short forwardly directed hairs; style 37 x c.1mm, sparsely scaly in the lower 1⁄3 and with forwardly directed, semi-patent hairs to within 3–4mm of the stigma; stigma irregularly lobed, c.1mm, cream, eventually protruding to 6mm from the mouth of the flower. Fruit 17–25 x 4–7mm, narrowly ellipsoid, strongly longitudinally grooved. Seeds 4–4.5mm, without tails c.1.1mm, the longest tail to 1.9mm.

Distribution

Indonesia, S Kalimantan (Borneo), Pergunungan, Meratus, Mt Halauhalau (G. Besar).

Altitude

Habitat

It grows in upper montane, mossy forest dominated by Phyllocladus, Drimys and Vaccinium and is common in open islands of scrub amongst bryophytes and lichens on the summit sandstone ridge.

Nomenclatural History

Notes

References

Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:162