Quercus bidoupensis Binh & Ngoc, 2018

Binh, Hoang Thi, Ngoc, Nguyen Van, Tagane, Shuichiro, Toyama, Hironori, Mase, Keiko, Mitsuyuki, Chika, Strijk, Joeri Sergej, Suyama, Yoshihisa & Yahara, Tetsukazu, 2018, A taxonomic study of Quercus langbianensis complex based on morphology and DNA barcodes of classic and next generation sequences, PhytoKeys 95, pp. 37-70 : 52-53

Quercus bidoupensis Binh & Ngoc sp. nov. Fig. 7

Diagnosis.

Similar to Quercus langbianensis s. str. in leaf shape, the number of secondary veins and basal scar of the nut convex, but distinguished in having bud oblong to ellipsoid (vs. globose to broadly ovoid), undulate and distinctly serrate leaf margin along the upper half (vs. regularly distinctly serrate in the upper 1/3), obconical cupules (vs. cup-shape), bracts of cupule arranged in 5-6 rings (vs. 6-9 rings), and nut ovoid (vs. obovoid to ellipsoid).

Type.

VIETNAM. Lam Dong Province: Bidoup-Nui Ba National Park, hill evergreen forest dominated by the species of Fagaceae , 12°09'52.95"N, 108°32'00.38"E, alt. 1,698 m, 24 Feb. 2016, Tagane S., Toyama H., Nagamasu H., Naiki A., Dang Son, Nguyen V. Ngoc, Wai J. V4328 (holotype: KYO!; isotypes: DLU!, the herbarium of Bidoup-Nui Ba National Park ) .

Description.

Tree, 8 m tall. Buds oblong to ellipsoid, ca. 2-4 mm high, ca. 1-2 mm in diam., scales 6-7 rows, imbricate, ovate-riangular, ca. 3 × 2.5 mm, apex obtuse, margin ciliate, densely hairy or glabrous outside, glabrous inside. Twigs greyish, glabrous, lenticellate. Leaf blades oblong-lanceolate, (7.5-)10-13 × 2.5-4 cm, thinly coriaceous, blackish-brown adaxially, pale brown abaxially when dry, glabrous on both surfaces, acuminate at apex, cuneate at base, margin undulate, distinctly serrate in the upper 1/2; midrib sunken adaxially, prominent abaxially, lateral veins 10-13 pairs, slightly prominent adaxially, prominent abaxially, at an angle of 45-50 degrees from midrib and running into the teeth of margin, tertiary veins scalariform-reticulate, slightly prominent, visible on both surfaces; petioles 1.3-2 cm long, blackish when dry, glabrous. Male and female inflorescences and infructescences not seen. Fruits 2.6 cm high (including cupule); cupules obconical, 1.3-1.5 cm high, 1.3-1.7 cm in diam., enclosing 1/3 of nut when mature, outside tomentose with whitish hairs to glabrous, inside villous with erect whitish hairs, wall ca. 2-3 mm thick, bracts arranged in 5-6 rings, margin of rings entire (without scale-like structure); nut ovoid, 2.2 cm high, 1.4 cm in diam., blackish, apex acute, basal scar 0.9 cm in diam., convex, glabrous. Fruits characters were obtained from the fallen materials.

Phenology.

Unknown. Fallen fruits were collected in February.

Distribution and habitat.

VIETNAM. Lam Dong Province: Bidoup-Nui Ba National Park. At present, this species is known only from the type locality.

Additional specimens examined.

Vietnam. Lam Dong Province, Lan Tranh , 12°04'08.5 ’’ N, 108°21'55.5 ’’ E, alt. 1,695 m, 18 June 2015, N. Nguyen, D. Luong, B. Hoang V3202 (DLU, FU) .

Etymology.

The specific epithet " Quercus bidoupensis " is derived from its type locality.

Figures

Figure 7. Quercus bidoupensis Binh & Ngoc. A Leafy twig B Abaxial side of mature leaf C, D Side view and base view of the cupule, respectively E Inside of cupule F Nut. Materials: A-F from Tagane et al. V 4328.