Morphology of Hoya megalaster Warb. Ex K. Schumann & Lauterb and Hoya pachyphylla Warb. Ex K. Schumann & Lauterb (Apocynaceae) from New Guinea, Indonesia

New Guinea is one the mega-diverse regions of the world and a host to 6% of the world’s biodiversity. Recently, land clearing and forest fragmentation associated with rapid economic growth have become growing threats to biodiversity in New Guinea. One of the several taxa of plants that is affected due to the rapid destruction of its known host plants is the genus Hoya. We describe the vegetative and reproductive morphology of two species of Hoya that are found in the primary forest of Papua in Ubiyau Village, a remote area in West Papua, Indonesia: Hoya megalaster and H. pachyphylla. Both species are perennial climbing epiphytes with opposite phyllotaxy, and short-lived cymes that are positively geotropic. The two species differ in leaf morphology. Hoya megalaster has a thin lamina, while the leaves of H. pachyphylla are succulent. We provide a list of characters that can potentially be used for future morphometric and phylogenetic studies on these two species.