Tên Khoa học: Lithocarpus dahuoaiensis Ngoc & L. V. Dung, sp. nTên tiếng Anh: Tên tiếng Việt: Dẻ đạ hoàiTên khác:
Evergreen tree, up to 35 m tall; young branchlets pubescent with white hairs, soon glabrous, greyish green in vivo and blackish brown in sicco; terminal buds ca. 10–12 mm long, bud scale 4–6 mm long, densely covered with whitish hairs. Stipules not seen. Leaves alternate, blades broadly elliptic to slightly obovate, ca. 15–27 × 6–11 cm, thickly coriaceous, base cuneate, margin entire, slightly recurved, apex acuminate or caudate, acumen ca. 5–10 mm long, glabrous adaxially, subtle short soft hairs abaxially; midrib slightly raised above, distinctly raised below glabrous, greenish yellow in vivo, reddish brown in sicco; secondary veins 11–12 pairs, clearly visible on both sides, flat to slightly prominent adaxially, prominent abaxially, veins curving smoothly and disappearing near margins, at an angle of 55–65 degree from the midrib, tertiary veins scalariform, invisible to faintly visible on both surfaces; petioles ca. 10–15 mm long, rounded, thickened, pubescent when young, glabrescent later. Flowers not seen. Infructescences erect, woody, 25 cm long, rachis densely adpressed hairy. Acorn solitary, ovoid or turbinate, 13–15 mm in height, 20–23 mm in diam. (including cupule); fruiting stalk 3–5 mm long, densely fulvous tomentose hair. Cupules, turbinate, base a little broader than the upper part, densely tomentose inside and invisible or subtle hairy outside, lamellate, wall woody, sometimes crackled, enclosing ca. 1/2–2/3 of the nut, 12–14 mm in height, 19–22 mm in diam., bractlets triangular, obscure, forming 6–7 dimly concentric flanges. Mature nut 19–22 mm in height, 20–23 mm in diam., densely white tomentose; scar created by cupule at the base is deeply concave, ca. 13–15 mm in diam.; wall woody, crackled; apex abruptly acuminate, ca. 1.5–2 mm in height.
Distribution and habitat
Vietnam (so far known from Lam Dong Province and Dong Nai Province split by a boundary along National highway 20).
The specific epithet is derived from the type locality, Da Huoai, Lam Dong Province, Central Highland Vietnam.
Data Deficient (DD). Three fruiting individuals were found at the type locality, along the Chuoi pass of the 20 National highway. In addition, a staff member of Dong Nai Culture and Nature Reserve has collected this species at Ma Da, Vinh Cuu, Dong Nai Province, indicating its wide distribution around the type locality. However, at present we have no reliable information on its population size. Further investigations are needed to determine the conservation status and actual population size in its natural habitat.