Tên Khoa học: Adinandra hongiaoensis H. T. Son & L. V Dung
Tên tiếng Anh:
Tên tiếng Việt: Súm hòn giao
Tên khác:

Evergreen, trees up to 10 m tall, young branches with dense gray hairs. Petiole is very short, almost sessile, white at the base; leaves alternate; leaf blade oblong or oblong-elliptic, 30-45 cm long and 8-12 cm wide, adaxial surface green, glabrous, abaxial surface light green, grayish-yellow hairy, midvein abaxially prominent extended in the form of wings, lateral veins inconspicuous, leaf base obtuse or cordate, apex acuminate, margins serrate. Flowers axillary, solitary or paired; peduncle 0.5-0.7 cm long, dense white hairs; bracts 2, ovate, 0.8-1.0 x 0.7-0.8 cm, abaxial surface with dense hairs, sepals ovate, 1.0-1.2 x 1.3-1.7 cm, abaxial surface grayish brown sericeous, apex slightly acute to sub-rounded; outer sepals thick, margins reddish hairs; inner sepals membranous, margins entire. Petals white, oblong to oblong- elliptic, 2.2-2.5 x 1.6-1.7 cm, apex obtuse, adaxial surface pubescent. Stamens numerous, in 2 whorls, 20-24 per whorl, 1.5-1.7 cm long; filaments 0.3-0.4 cm long, with dense hairs, adnate to base of sepals; anthers linear, 0.2-0.3 cm long. Ovary conical shaped, locules 5, 18-45 ovules per locule; styles 5 lobed, shallow, 0.4¬0.6 cm long. Fruit purplish black, globose, 2-2.2 cm in diam., pubescent, many seeds per locule. Seeds brown-black, semicircular, kidney-shaped, 0.1-0.3 mm long, back creased (not smooth).

Distribution and habitat: The new species Adinandra hongiaoensis is endemic to Bidoup Nui Ba National Park, in the southern highlands of Vietnam, between 1600-2000 m a.s.l. associated with Fokienia hodginsii Henry & Tomas (Cupressaceae), Podocarpus imbricatus Blume, Podocarpus neriifolius D. Don (Podocarpaceae), Quercus macrocalyx Hick. & A. Camus, Quercus langbianensis Hick. & A. Camus (Fagaceae) and Camellia sp. (Theaceae).