Hoya paradisea Simonsson & Rodda, 2022

Hoya paradisea Simonsson & Rodda View in CoL , sp. nov. — Fig. 11 View Fig

Similar to Hoya juhoneweana Simonsson & Rodda subsp. juhoneweana in corolla shape and size (campanulate,> 2.5 cm diam) and in corona/corona diam ratio (corolla> 3 times as wide as corolla) but distinguished on corolla pubescence (inside glabrous except for a pubescent ring beneath the corona and the entire margin of corolla covered with stiff, brittle, c. 3 mm long hairs in H. paradisea , vs thickly pubescent inside, usually almost glabrous near centre in H. juhoneweana subsp. juhoneweana ), and leaf orientation and pubescence (not pendulous, glabrous in H. paradisea , vs pendulous, both surfaces covered by very stiff,erect, 1 mm or longer hairs in H. juhoneweana subsp. juhoneweana ). — Type: N. Simonsson & F. Juhonewe NS 0115 L (holo SING), Papua New Guinea,Western Province, Black River near Dahamo vil- lage, 100 m in lowland primary forest, living accession NS11­159, vouchered in cultivation in Stockholm, Sweden on 25 Mar. 2018 .

Etymology. The name refers to the exceptionally diverse rainforests of

New Guinea which are sometimes called Paradise forests.

All measurements are from live material, measurements in brackets indicate dry size.

Epiphytic climber with white latex in all vegetative parts. Stems up to 5 m long, cylindrical, 1–2 mm diam, sparsely pubescent, green; older stems lignified, up to 4 mm diam, glabrous, greyish brown, often sending horizontal flowering branches with densely spaced internodes of 1–2 cm long, while the main climbing stems often have 5–15 cm long internodes. Adventitious roots numerous, scattered along the stems. Leaves: petiole 3–6 by c. 1 mm, sparsely pubescent turning glabrescent, lamina elliptic-lanceolate, coriaceous, 5–8 by 1.5–3 cm, medium green on both surfaces, apex caudate, base round to attenuate; venation pinnate, midrib depressed on adaxial surface, secondary veins more or less obscure, glabrous. Basal colleters often missing, when present one, ovoid, 0.3–0.4 mm long. Inflorescence one per node, extra-axillary, pseudo-umbellate, positively geotropic, convex, consisting of 7–10 flowers lasting about 2 days; peduncle terete, c. 4–10 cm by c. 1 mm, light green to brownish, glabrous to minutely pubescent, older peduncles forming a rachis from previous flowerings, but occasionally dropped after flowering; pedicels terete, c. 3 cm by 1 mm, light green, glabrescent. Calyx c. 6 mm diam; lobes acute, c. 1.5 by 1 mm, apex acute. Colleters not observed. Corolla campanulate, c. 3 cm diam in natural state ( 4.5–5 cm when flattened or c. 1.5 cm when dry in natural state), creamy white with very slight pinkish or yellowish hue, outside glabrous, inside glabrous except for a pubescent ring beneath the corona and the entire margin of corolla covered with stiff, brittle, c. 3 mm long hairs; tube c. 3 cm diam (c. 1.5 cm diam), c. 1 cm deep; lobes broadly triangular, c. 1.4 by 1.6 cm (7–9 by 8–10 mm). Corona staminal, c. 4 (3–3.5) mm high, c. 7 (4.5–5.5) mm diam, fleshy, translucent creamy yellow with a maroon centre; lobes from above ovate, almost heart-shaped, c. 3 by 2.5 mm, inner processes horizontal and rounded, not touching each other in the centre, outer processes pointing upward and rounded, with basal revolute margin going almost all the way up to highest point of the corona, not basally fused with the filament tube. Pollinia oblong-ovate, c. 700 by 250 µm, with pellucid margin; corpusculum oblong with a constriction in the middle, 300–350 by c. 200 µm; caudicles attached at the lower half of the corpusculum, c. 150 by 50 µm. Ovary conical, c. 2.5 mm long, glabrous. Fruit and seed not observed.

Distribution — This species was first collected in 2011 during an expedition along the Black River, the type locality, and has not been recorded elsewhere during other expeditions in Papua New Guinea. In 2021 we received photographic records of two additional collections from Mimika regency in Indonesian Papua province (Mt Timika area), indicating a wider distribution area (Imran pers. comm.). The species may be more common in southwest New Guinea, which is still much unexplored.

Habitat & Ecology — An epiphytic climber in lowland primary riverine forest, often growing near the ground or near streams on trees and shrubs. At the type locality it was not observed in taller trees or sunnier and drier spots, only in shade or filtered sunlight. Locally common at the type locality.

Conservation status — Data Deficient (DD; IUCN 2012). This species has only been vouchered at the type locality where it appears to be locally common. Much of Papua New Guinea’s Western Province’s lowland rainforest has been, or is being, logged ( Shearman et al. 2009) and the type locality is not inside a protected area and may be lost in the near future. The two records in Mimika regency, Papua Province, suggest that H. paradisea may be much more widespread and it is possible that it might be found in Lorentz National Park. The conservation assessment will need to be updated once more collections become available.

Notes — It is the only Hoya species in New Guinea having c. 3 mm long and very brittle hairs along the margins of the campanulate flowers, that move with the slightest air movement. It is here compared with H. juhoneweana subsp. juhoneweana because of the similarities in the corolla shape (campanulate) and in the small corona in comparison to the size of the corolla. It is not compared with H. juhoneweana subsp. lindforsiana Simonsson & Rodda , because this subspecies has a rotate corolla. The similarities with H. juhoneweana subsp. juhoneweana , however, do not automatically make it a subspecies of H. juhoneweana and the two taxa may not be closely related as other characters such as the leaf orientation and pubescence are quite different. They occur in different habitats, H. paradisea growing in the lowlands, H. juhoneweana subsp. juhoneweana from above 1300 m. Outside of New Guinea, H. devogelii Rodda & Simonsson also has campanulate flowers with long (c. 2 mm long) hairs on the corolla lobes. The two species can be separated on leaf shape, texture and size (linear-lanceolate, fleshy, 10–15 by 1–2 cm in H. devogelii and elliptic-lanceolate, coriaceous, 5–8 by 1.5–3 cm in H. paradisea ) and corona morphology (stipitate, round when observed from above in H. devogelii ; sessile, distinctly 5-lobed in H. paradisea ). When not in flower, H. paradisea can be confused with many other New Guinean species with similar plain green, coriaceous leaves, for example H. apoda S.Moore , H. evelinae Simonsson & Rodda , H. leucantha S.Moore , H. oreostemma Schltr. , and H. solaniflora Schltr. Their flowers show a great diversity in both size, shape, colour and orientation, but none of them have corolla lobes with 3 mm long hairs. The flowers of H. paradisea last about two nights only, and emit a very pleasant and noticeable scent during the night similar to a mixture of rose and citrus, reminding of the scent of rose geranium ( Pelargonium graveolens L’Hér. hybrids, Geraniaceae ).