Scientific name: Hiepia corymbosa V.T.Pham & Aver.
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Hiepia corymbosa was observed as a humus or bark epiphyte on old mossy trees in primary broad-leaved evergreen forests along rocky river canyons composed with shale, sandstone and solid crystalline highly eroded limestone at elevation 300–500 m a.s.l. Samples of this plant were found in tree canopies along stream just along water line. Plants commonly settle down in forks of tree branches in more or less sunny places. The species of Aglaia, Antidesma, Artocarpus, Baccaurea, Canarium, Cryptocarya, Diospyros, Dipterocarpus, Dracontomelum, Dysoxylon, Elaeocarpus, Erismanthus, Ficus, Litsea, Manglietia, Michelia, Phoebe, Pometia, Sloanea, Sterculia, Stixis, Streblus, Sygyzium were observed as the most common trees in habitats of H. corymbosa as well as numerous palms, mainly Arenga caudatum, A. westerhoutii, Rhapis excelsa and species of Caryota and Pinanga. Some epiphytic ferns and orchids were observed as usual associates growing together with Hiepia corymbosa. Among such species most common are Bulbophyllum delitescens, B. longiflorum, Dendrobium terminale, D. truncatum, Kingidium deliciosum, Lemmaphyllum microphyllum, Phalaenopsis mannii, Pomatocalpa spicatum, Pyrrosia lanceolata and Thrixspermum centipeda. Among strict Vietnamese endemics found in habitats of newly discovered genus, Epipactis atromarginata, Eria thao, Ixodonerium annamense, Micropera poilanei and Pteroceras simondianum should be mentioned.

Hiepia corymbosa commonly inhabits lowland rocky river valleys composed with shale, sandstone and limestone in Quang Binh (Minh Hoa district, Thuong Hoa municipality) and Quang Tri provinces (Da Krong district, Ta Rut municipality) of central Vietnam growing at elevation 300–500 m a.s.l. Most probably, discovered plant represents the pattern of strict endemism typical for highly endangered lowland aboriginal floras of Central Vietnam.

IUCN Red List category. Hiepia corymbosa is local Vietnamese endemic, which inhabits very limited areas in Quang Binh and Quang Tri provinces in central part of the country. Both known localities are currently endangered due to deforestation and human land exploitation. The species is certainly very rare and actually is known only from two populations with less than 10 observed mature individuals. Typical habitat areas extend along narrow river valleys with total land occupancy not more than 2–3 km². Vegetation supported known populations is highly depressed by anthropogenic activity and can be destroyed in the near future. According to accepted criteria (IUCN, 2010, version 8.1), H. corymbosa should be treated as critically endangered species and genus (CR) approaching full extinction in the nature.