Hoya of Papuasia I. 
145 
remaining forest in that area is above 1500 m and thus in a different climate zone, 
making it unlikely that this taxon thrives in those forests. 
Additional specimens examined. PAPUA NEW GUINEA: Morobe Province: Bupu Village 
above Gurakor, rainforest, 2400 ft [c. 730 m], 7°00'S 146°40'E, 27 Jul 1968, Millar, A.N. NGF 
12172 (L [L2726757], LAE); Mumeng subdistrict, Bupu village, 914 m, mountain ridges, 
Castanopsis forest, 7°00'S 146°35'E, 15 May 1974, Katik, P. & Larivita, G. LAE 62031 (BRI 
n.v., CANB n.v., L [L2726758], LAE); Bula, 744 m, 07°00'59"S 146°56'44"E, 16 Feb 2008, 
living accession NS08-030, vouchered at Ukarumpa on 29 Jun 2012 as Simonsson Juhonewe, 
N. & Juhonewe, F. NS0047L (LAE Spirit in SING). 
Notes. Similar to Hoya stenophylla Schltr. in the linear leaves, a character unique 
to these two species in PNG. They can be easily distinguished by Hoya yvesrocheri 
having an evenly green colour in all vegetative parts except for older stems, leaves 
twice the width, and in its unique floral development where the flowers of a single 
inflorescence are in different stages with only one or rarely two flowers open at a time. 
In Hoya stenophylla all flowers develop simultaneously, the usual pattern for most 
Hoya species. 
ACKNOWLEDGEMENTS: This study is part of an on-going research project on the 
systematics of Hoya. Nadhanielle Simonsson Juhonewe received support from the Yves 
Rocher Foundation, Helge Ax:son Johnsons Stiftelse and many individual contributors. 
Michele Rodda received support from the National Parks Board (Singapore), which sponsored 
numerous herbarium trips to Asian and European herbaria, and from the SYNTHESYS Project 
http://www.synthesys.info/ which is financed by the European Union under the FP7 Integrating 
Activities Programme, grants GB-TAF-5657, NL-TAF-676 and DE-TAF-675. We would like to 
thank the curators of the herbaria mentioned in the text for allowing access and/or for providing 
high quality images of herbarium specimens. We thank Paul Forster and the late David Liddle 
for their encouragement to work on Papuasian Hoya , Theresa Sulemana for the permission to 
use her photograph of Hoya yvesrocheri, Stephanie Pimm Lyon for the permission to use her 
photographs of Hoya juhoneweana ssp. juhoneweana in habitat, Foreting Juhonewe for the 
permission to use numerous photographs, and two anonymous reviewers for their valuable 
comments on the manuscript. 
References 
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Forster, PI. (1995). Circumscription of Marsdenia (Asclepiadaceae: Marsdenieae), with a 
revision of the genus in Australia and Papuasia. Austral. Syst. Bot. 8: 703-933. 
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