Hoya leucantha S.Moore

Hoya leucantha S.Moore View in CoL — Fig. 1 View Fig , 2 View Fig

Hoya leucantha S. Moore (1916) View in CoL 115. — Lectotype (designated here): Boden Kloss s.n. (lecto BM [ BM000895752 ]), Indonesia, Papua Province, Utakwa River to Mt. Carstensz , Canoe Camp.

Climber, likely epiphytic, producing both twining stems and horizontal to pendulous, straight stiff stems, latex white. Stems cylindrical, slender, 1–1.8 mm diam, sparsely pubescent, internodes 2–7 cm long. Roots not observed. Leaves: petiole terete, channelled above, 1.5–2.5 by c. 0.5 mm, pubescent; lamina lanceolate, chartaceous, 18–45(–70) by 6–12(–15) mm, apex acuminate, base rounded or attenuate, glabrous; venation pinnate, midrib depressed on adaxial surface, secondary veins 6–10 each side. Basal colleters one, narrowly conical, c. 0.3 mm long. Inflorescence one per node, positively geotropic, pseudo-umbelliform, consisting of 20–30 flowers; peduncle extra-axillary, terete, 14–40 by c. 3 mm, older peduncles forming a rachis from previous flowerings, pubescent; pedicels filiform, 18–23 by c. 0.3 mm, glabrous. Calyx c. 2 mm diam; lobes narrowly deltate, 0.8–1 by c. 0.35 mm, apex rounded, glabrous. Basal colleters one at each calyx lobe sinus, ovate, c. 0.2 mm long. Corolla rotate, star-shaped, 12 –15 mm diam when flattened; tube c. 3 mm long, cream to pale yellow or pink, outside glabrous, inside pubescent; lobes deltate, 5–6 by 4–4.5 mm, apex acuminate, cream to pale yellow or pink, outside glabrous, inside densely pubescent. Corona staminal, central part conical, surrounded by spreading or downcurved lobes, 2.3–2.6 mm high, 3.5–4.5 mm diam; lobes with an inner process erect, oblong, c. 1.5 by 0.5 mm, apex rounded, pale yellow, apically sometimes red, and a spreading outer process, oblong, 1.5– 1.7 by 0.7–0.8 mm, apex rounded, cream to yellow, with basal revolute margins. Pollinia View in CoL oblong, 380–220 by 130–150 µm, with pellucid margin; corpusculum oblong with a central constriction, 150–170 by 80–90 µm; caudicles oblong, c. 100 µm long. Ovary narrowly conical, c. 1 by 0.2 mm, glabrous. Fruit and seed not observed.

Distribution — Known from three localities in Indonesia, West Papua Province: the type collection from Utakwa River, one specimen from Bomberai Peninsula, and one unvouchered record from Mimika regency (near Timika town) in Papua province (Imran, pers. comm.).

Habitat & Ecology — Unknown, it appears to be a lowland species, found along rivers.

Conservation status — Data Deficient ( DD; IUCN 2012 ). Known only from the type specimen collected 106 years ago, a second collection from 59 years ago and a recent unvouchered collection, more collections and habitat data is needed before the conservation status can be assessed .

Specimens examined. INDONESIA, West Papua Province, Bomberai Peninsula, Kwafa, Sjuga-Wagura area , 26 Apr. 1963, BW ( V. W. Moll) 13035 ( L [ L0834583 ]) .

Note — The protologue of H. leucantha only mentions the type collection as ‘Canoe camp 500ft’ ( Moore 1916). The only original material available for typification is Boden Kloss s.n. (BM [BM000895752]), which is therefore designated as the lectotype for the name. The shape of the corona of H. leucantha is uncommon among New Guinean species, consisting of a central conical portion formed by the inner lobe processes, surrounded by oblong spreading or downcurved outer processes. This is only partially visible in the small buds present on the type specimen. There the corona lobes have an erect inner process of c. 1 mm tall and a basally attached outer process ovoid, c. 0.3 mm long. Hoya leucantha is somewhat similar to Hoya patella Schltr. in corona morphology, as both species have erect, oblong inner corona processes and spreading narrow, oblong outer corona lobe processes, but they can be separated on peduncle length, number of flowers per inflorescence and corolla type and size (peduncle 1.4–4 cm long, 20–30 flowers per inflorescence, corolla rotate, 12–15 mm diam in H. leucantha vs peduncle 2– 3 mm long, 1– 2 flowers per inflorescence, corolla broadly campanulate, 3–4 cm diam in H. patella ).