Hoya domaensis Rodda & Simonsson, 2022

Hoya domaensis Rodda & Simonsson View in CoL , sp. nov. — Fig. 3 View Fig

Similar to Hoya pulchella Schltr. in corolla shape and size (campanulate, 1.5–2.5 cm diam) and leaf shape (elliptic to ovate), but distinguished by leaf size, texture and pubescence (coriaceous, 1.7–2.2 by 0.9–1.3 cm,glabrous to sparsely pubescent in H. pulchella ; chartaceous, 3–5.5 by 1.7–2.2 cm, sparsely pubescent above,pubescent below in H. domaensis ); corona lobes texture (fleshy and dark crimson in H.pulchella , membranous and translucent in H. domaensis ). — Type: P.J.B Woods 151 (holo E; iso LAE), Papua New Guinea, Northern District (now Oro Province), West of Doma, near the track between Debana and Doma, S9°45' E148°29', 26 Oct. 1962.

Etymology. Hoya domaensis is named after Doma, the type locality.

Climber, epiphytic, latex colour unknown. Stems cylindrical, slender, 1–1.5 mm diam, sparsely pubescent to glabrescent, internodes 6–10 cm long. Roots adventitious. Leaves: petiole terete, 3–5 by c. 0.8 mm, pubescent; lamina ovate to elliptic, chartaceous when dry, 3–5.5 by 1.7–2.2 cm, sparsely pubescent above, pubescent below, apex acuminate, shortly caudate, base rounded; venation pinnate, secondary veins 3–8 each side. Basal colleters one at each lamina base, globose, c. 0.2 mm long. Inflorescence one per node, tropism unknown, likely positive, likely consisting of a single open flower; peduncle extra-axillary, terete, c. 8 by 0.8 mm, older peduncles forming a rachis from previous flowerings, glabrous; pedicels filiform, 10–13 by c. 0.3 mm, glabrous. Calyx c. 5.5 mm diam; lobes oblong, c. 2 by 1 mm, apex acuminate, outside sparsely pubescent, inside glabrous. Basal colleters not observed; bud shape unknown. Corolla campanulate, 1.5–2.5 cm diam, creamy white with a slight pinky-brown flush near calyx and at apex of lobes; tube 10–15 mm long, outside glabrous, papillose, inside pubescent; lobes triangular, 4–5.5 by 10–12 mm, apex acute, outside glabrous, papillose, inside pubescent. Corona staminal, height uncertain, likely c. 2 mm (much flattened on the specimen), c. 11 mm diam; lobes spreading, broadly ovate, membranous and translucent, 4.5–6 by 3–4 mm, inner process acute with a rounded tip, outer processes truncate, slightly concave, basal revolute margins not observed. Pollinia oblong, c. 450 by 200 µm, without pellucid margin; corpusculum rhomboid, c. 220 by 150 µm; caudicles attached to the lower half of the corpusculum, c. 130 µm long. Ovary not observed. Fruit and seed not observed.

Distribution — The species is only known from the type locality west of Doma, Oro Province, Papua New Guinea.

Habitat & Ecology — No habitat information was provided on the type specimen. Based on the GPS coordinates indicated on the specimen label, H. domaensis is found in montane forests at about 1100 m altitude.

Conservation status — Data Deficient ( DD; IUCN 2012 ). Hoya domaensis is known only from the type specimen collected 60 years ago .

Note — This is a very unusual species because it has membranous and seemingly translucent corona lobes, unlike any species of Hoya discovered so far, where the lobes are generally fleshy and opaque. In New Guinea it is only vaguely similar and likely unrelated to a group of species that include H. microphylla , H. oxycoccoides . H. pulchella and H. venusta Schltr. They are all delicate epiphytic climbers with small leaves, wiry stems and snow-white flowers with red to maroon centres. Hoya pulchella has elliptic to ovate leaves and a broadly campanulate corolla of c. 2.5 cm wide, and it is therefore more similar to H. domaensis , while the other species have a more rotate corolla of c. 2 cm wide; H. microphylla has lanceolate to ovate leaves of 1–2 cm long; H. venusta has stouter stems and peduncles, and larger lanceolate leaves (up to 5 cm long); H. oxycoccoides has 1–1.5 cm long round leaves.

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