Rhododendron dianthosmum Sleumer

Blumea 1963. 12: 100.

WFO ID: wfo-0000400742

IPNI ID: urn:lsid:ipni.org:names:332328-1

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Description

Shrub to 2m. Twigs slender, densely scaly, early glabrescent and often whitish; internodes 6–16cm. Leaves 3–4 together in pseudowhorls at the upper 2 or 3 nodes. Blade 70–140 x 30–55mm, broadly elliptic or elliptic or slightly obovate; apex broadly acute to obtuse; margin entire, flat, a little recurved when dry; base broadly tapering to rounded, young leaves densely reddish-brown stellate-scaly, mature ones glabrescent, on both sides covered with numerous epidermal tubercles which make them feel rough to the touch. Scales dendroid; marginal zone divided to, or almost to, the centre; centre small, deepened or prolonged into a short stalk. Mid-vein slightly prominent proximally above, gradually becoming flat in the distal part above; below as thick as the petiole in the proximal part, gradually decreasing distally; lateral veins 8–12 per side, irregular, inarched before the margin, slightly prominent on both sides, veins laxly reticulate, not very conspicuous. Petiole 10–15 x 2–2.5mm, densely scaly initially. Bracts 10–35 x 10–15mm, dull red; outer ones ovate, inner ones elliptic-ovate and apiculate, innermost ones broadly spathulate, scaly and/or appressed-hairy. Bract­eoles c.20 x 1–2mm, linear, glabrous. Inflorescence a 3–6-flowered open umbel, the flowers held stiffly horizontally or half-hanging. Pedicels 10–15 x 1.5mm, very densely brown stellate-scaly, without hairs. Calyx c.3mm in diameter, obliquely disc-shaped. Corolla 50–70 x c.70mm, pure white, or pink with darker pink edges, with a scent of carnations; tube 25–40 x 6–10 x 12–15mm, tubular, straight, glabrous outside, shortly hairy inside; lobes 6–7 in number, 20–35 x 20–30mm, spathulate, 3 or 4 of them generally smaller than the others, horizontally spreading. Stamens exserted to c.10mm; filaments linear, densely or more laxly hairy in the proximal ¾, glabrous distally; anthers 3.5–4 x c.1mm, elongate-oblong, the base obtuse. Disc glabrous below, hairy at the upper margin. Ovary 8–10 x 2–3mm, sub-cylindrical, covered with whitish to yellowish, distally directed hairs, which cover the scales, tapering gradually; style c.30mm, slender, densely hairy proximally, the hairs becoming laxer distally and completely glabrous in the uppermost ¼, without scales; stigma 2.5–3mm.

Distribution

Indonesia, New Guinea (W), above Jayapura on the W slope of Mt Dafonsero; Cycloop Mts, Faita R. camp and along path from Ifar to Ormu.

Altitude

Habitat

Epiphytic in primary forest, 800–1400m, descending along ravines to c.500m.

Nomenclatural History

Notes

References

Argent, G. (2006) Rhododendrons of subgenus Vireya. RHS:London. Page:79