Gardens’ Bulletin Singapore 69(1): 97-147. 2017 
doi: 10.3850/S2010098116000093 
97 
Contribution to a revision of Hoya 
(Apocynaceae: Asclepiadoideae) of Papuasia. 
Part I: ten new species, one new subspecies 
and one new combination 
N. Simonsson Juhonewe 1 & M. Rodda 2 
‘Research affiliate at National Research Institute of Papua New Guinea 
Home address: PO Box 1 - 524, Ukarumpa, EHP 444, Papua New Guinea 
2 Herbarium, Singapore Botanic Gardens, National Parks Board, 
1 Cluny Road, Singapore 259569 
rodda. michele@gmail. com 
ABSTRACT. The large majority of Hoya R.Br. species known from Papuasia were described 
in the first half of the 20th century and most of these are endemic. Along with Borneo and the 
Philippines the region is a centre of diversity of the genus. Since 2006 herbarium materials 
have been studied for a revision of Hoya of New Guinea along with field investigations on 
Papuasian Hoya since 2010. In the present paper we publish ten new species, Hoya brassii 
PI.Forst. & Liddle ex Simonsson & Rodda, H. carrii PI.Forst. & Fiddle ex Simonsson & 
Rodda, H. edholmiana Simonsson & Rodda, H. evelinae Simonsson & Rodda, H. juhoneweana 
Simonsson & Rodda, H. krusenstierniana Simonsson & Rodda, H. koteka Simonsson & 
Rodda, H. stenakei Simonsson & Rodda, H. versteegii Simonsson & Rodda and H. yvesrocheri 
Simonsson & Rodda, one subspecies, H. juhoneweana ssp. lindforsiana Simonsson & Rodda, 
and make one new combination, H urniflora (PI.Forst.) Simonsson & Rodda, which is also 
lectotypified. 
Keywords. Indonesia, Marsdenieae, Papua New Guinea 
Introduction 
Hoya R.Br., with an estimated 350—450 species (Rodda, 2015), is the largest genus 
in the Apocynaceae. The most species-rich regions for Hoya are in tropical and 
subtropical South Asia, Southeast Asia and Papuasia. The genus also extends to the 
Himalayan foothills to the northwest, Okinawa (Japan) to the northeast, Australia to 
the south and the Fiji Islands to the southeast. The plants are generally epiphytic or 
hemi-epiphytic climbers or have a pendulous habit, with a few shrubby species (Rodda 
& Ercole, 2014; Rodda et al., 2014a). 
Recent regional revisions are only available for Peninsular Malaysia (Rintz, 
1978), China (Fi et al., 1995) and Australia (Forster & Fiddle, 1996). A guidebook 
to Hoya of Borneo has just been published (Famb & Rodda, 2016) but a revision for 
the island is still in preparation (Rodda, in prep.). Species diversity is highest in the 
Malesian islands, in particular in the Philippines, Borneo and New Guinea. In both the 
Philippines and Borneo the number of species known has dramatically increased in 
