Hoya of Papuasia I. 
143 
New Guinea, Morobe Province, Wagau, 4200 ft [c. 1280 m], found in large tree in old 
garden near village, 6°50'S 146°50'E, 11 June 1964, Millar, A.N. NGF 23466 (holotype 
LAE; isotypes L [L2726759], CANB n.v.). (Fig. 24) 
Liana slender, glabrous with white latex in vegetative parts. Leafy stems cylindrical, 
1-2 mm in diam; older stems lignified, max diameter (up to 3-4 mm in diameter), colour 
greenish brown, bark peeling; internodes 1-5(10) cm long. Leaves usually hanging, 
petiolate; petiole terete, c. 2-5 x 1-1.5 mm in diameter, green without markings; 
lamina linear or slightly lanceolate, coriaceous, carinate, c. 5-10 x 0.5-1 cm, green on 
both surfaces, apex acute base rounded or attenuate, margin entire; venation pinnate 
but barely evident in living material, midrib depressed on adaxial surface, secondary 
veins 4-6 each side, secondary veins anastomosing near leaf margin, branching from 
the midrib at c. 60-90°; leaf colleters 1 or 2, conical 0.3-0.4 mm long. Inflorescences 
one per node, extra-axillary, positively geotropic, pseudo-umbellate, usually 1-8 buds 
at different stages with only one or rarefy two flower open at a time; peduncle terete, c. 
0.5-3 x 0.1-0.15 cm, older peduncles bearing scars from previous flowerings, pedicels 
terete, 2 cm x 0.5-1 mm, green. Calyx c. 3 mm in diameter, lobes triangular-ovate, c. 0.5 
x 0.5 mm, glabrous. Corolla campanulate, c. 1.5 cm diameter (c. 2 cm when flattened), 
white with a slight pink or purple hue, intensifying with more sunlight; tube c. 7 mm, 
lobes triangular, acuminate, c. 6 x 7 mm, margins entire, apex slightly revolute, densely 
pubescent with unicellular hairs, abaxially glabrous. Corona staminal c. 2 mm high, 5 
mm in diameter, fleshy, creamy white-yellow with dark reddish centre; corona lobes 
elliptic-ovate, c. 2 x 1 mm, inner processes slightly erect, outer processes rounded and 
erect, with basal revolute margins. Style-head hidden by anther appendages. Pollinia 
oblong, c. 350 x 130-150 pm, with sterile edge, corpusculum 150-200 x 100-110 pm, 
caudicles attached to middle of corpusculum, c. 70 x 30 pm. Ovary conical, c. 0.8 mm 
long, glabrous. Fruits and seeds unknown. 
Distribution. Recorded from Morobe Province only, at altitudes between 720 and 
1260 m. 
Etymology. Named after the Yves Rocher Foundation which supported the first 
author’s Hoya Project for five years during 2011-2015. 
Habitat and ecology. It seems to be confined to altitudes between 700 and 1300 metres 
within a small area in Morobe province. The first author has only seen it once, on a 
fallen tree on a very sharp ridge in primary rainforest in Bui a, Morobe Province. Upon 
re-visiting the area in 2013 the ridge had been burned for expanding slash-and-burn 
subsistence gardens. 
Provisional IUCN conservation assessment. Endangered EN Blab(i,iii) (IUCN, 
2016). Hoya yvesrocheri has only been found in Morobe Province between 700 and 
1300 m, an altitude where the few remnants of forest are rapidly being converted into 
subsistence gardens or abandoned grasslands due to the expanding population. Most 
