Hoya is a genus in the Asclepiadoideae, the milkweed subfamily of the flowering-plant family Apocynaceae. In the past decade, 15 new Hoya were reported in China. Together with the newly reported species and those recorded in the Flora of China, there are approximately 47 species and one variety of Hoya currently recognized in China.
During an expedition to survey the vascular plants of Longling Xiaoheishan Nature Reserve, Yunnan Province in SW China, researchers encountered a unique Hoya in bloom.
“After carefully studying the living plants and specimens, and comparing with all available literature and herbarium resources, we confirmed that the species was distinct from any described species,” said TAN Yunhong of Xishuangbanna Tropical Botanical Garden (XTBG).
The researchers named the new species as Hoya gaoligongensis and got it published in Phytotaxa.
Hoya gaoligongensis is an epiphytic climbing liana, with milky latex in all parts. Its stems are often with adventitious roots, glabrescent, and the leaves are opposite. The blades are thick, rigid-coriaceous, oblong, long-oblanceolate or spatulate.
Hoya gaoligongensis is similar to H. yuennanensis and H. globulosa, but can be clearly distinguished from the two species by its leaf and floral characters. Compared to the latter two species, H. gaoligongensis has narrower long oblanceolate leaves, much smaller lateral vein branching angles, and inconspicuous lateral veins.
Although the corolla is similar in all three species, the relative positions of outer and inner corona lobe processes serve as a key character distinguishing these species.
Hoya gaoligongensis is known from Longling, Gongshan, and Deqin, W/NW Yunnan Province, an epiphytic liana growing on the surface of giant trees in mid-elevation (2000–2400 m) moist evergreen broadleaved forest. Its conservation status is recognized as vulnerable.
TAN Yunhong Principal Investigator
Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
Inflorescence of Hoya gaoligongensis (Image by TAN Yunhong)
Habitat of Hoya gaoligongensis (Image by TAN Yunhong)