Hoya pulleana Rodda & Simonsson, 2022

Rodda, M. & Simonsson, N., 2022, Contribution to a revision of Hoya (Apocynaceae: Asclepiadoideae) of Papuasia. Part II: eight new species, one new subspecies, Blumea 67 (2), pp. 139-155 : 150-152

Hoya pulleana Rodda & Simonsson , sp. nov. — Fig. 12, 13

Similar to Hoya oxycoccoides in the small ovate to rounded leaves, thin wiry stems and rotate corollas, but differs by having thicker leaves ( 1–1.5 mm thick in H. pulleana vs < 1 mm in H. oxycoccoides ) and flower size ( 7–10 mm diam in H. pulleana vs c. 2 cm diam in H. oxycoccoides ). — Type: A. Pulle 1217 (holo L [ L0834578 ]; iso BO [ BO0110493 ]), Indonesia, Papua Province, Lorentz River (Sungai Unir) near Kloofriver , 40 m, 24 Mar. 1913 .

Etymology. Named after its collector,August Adriaan Pulle (1878–1955).

Climber, likely epiphytic, with white latex in all vegetative parts. Stems cylindrical, slender, 1–2 mm diam, pubescent to glabrescent, internodes 1–4(–10) cm long. Roots not observed. Leaves: petiole terete, 2–3 by 0.4–0.8 mm, pubescent; lamina ovate to round, 1–1.5 mm thick and very coriaceous when dry, 8–16 by 5–12 mm, glabrous above, sparsely pubescent to glabrescent underneath, apex rounded, occasionally shortly apiculate, base rounded to very shallowly cordate; venation pinnate, secondary veins 3–5 each side, barely visible. Colleter 1 at each lamina base, globose, 0.2–0.25 mm long. Inflorescence one per node, negatively geotropic, pseudo-umbelliform, consisting of 3–9 flowers; peduncle extra-axillary, terete, 5 –7 cm by 0.8–1 mm, older peduncles forming a rachis from previous flowerings, pubescent; pedicels filiform, 10–22 by c. 0.3 mm, pubescent. Calyx c. 3 mm diam; lobes oblong, 1.2–1.5 by 0.6–0.8 mm, apex rounded, outside sparsely pubescent, inside glabrous, ciliate. Basal colleters one at each calyx lobe sinus, ovate, c. 0.1 mm long. Buds globose. Flowers white to light yellow-green. Corolla rotate, 7–10 mm diam when flattened; tube c. 1.5 mm long, outside glabrous, inside pubescent, glabrescent towards the centre; lobes elliptic-ovate, 3–3.5 by 3–3.2 mm, apex acute, outside glabrous, inside pubescent, margins recurved. Corona staminal, c. 1.7 mm high, c. 3.5 mm diam; lobes broadly elliptic, 1.5–1.8 by 0.9–1.1 mm, inner process acuminate, erect, c. 1 by 0.1 mm, outer processes raised, forming an acute angle with the inner process, apex rounded, with basal revolute margins. Pollinia oblong, c. 600 by 250 µm, with pellucid margin; corpusculum rhomboid, c. 350 by 250 µm; caudicles attached at the lower half of the corpusculum, c. 150 µm long. Ovary narrowly conical with a globose base, c. 1.7 mm long, base c. 0.7 mm wide, glabrous. Fruit and seed not observed.

Distribution — Only known from two localities in the southern part of Indonesia’s Papua province, near Sungai Unir and at Kelurahan Iwaka, Iwaka, Mimika Regency.

Habitat & Ecology — The label on the type specimens only mentions the habitat as ‘forest’. The plant observed at Kelurahan Iwaka was found in lowland riverine forest (Imran pers. comm.).

Conservation status — Data Deficient ( DD; IUCN 2012 ). The only vouchered collection is the type specimen collected 109 years ago, and the recent sighting in Indonesia at Kelurahan Iwaka .

Note — Forster and Liddle suggested to use the name ‘ dischidioides ’ for this species and labelled the type specimen with this name. However, we feel that the small leaves are the only resemblance between H. pulleana and some species of Dischidia R.Br. , while the flowers are very much within the morphological variation of Hoya species. There are numerous small-leaved Hoya species in New Guinea, but the majority of them are found in montane forest. Among species with similar leaves only H. oxycoccoides has been recorded from the lowlands; its leaves are thinly coriaceous, the flowers of H. oxycoccoides are c. 2 cm diam, with flat corolla lobe margins and a maroon corona, while H. pulleana has 1–1.5 mm thick and very coriaceous leaves, 3– 9-flowered umbels with flowers 7–10 mm diam and recurved corolla lobe margins making the white corona the dominant feature of the flower.