Beilschmiedia danhkyii B.H.Quang, V.H.Nguyen & Tagane, 2021

Quang, Bui Hong, Tagane, Shuichiro, Viet, Hung Nguyen & Canh, Toan Thai, 2021, Beilschmiedia danhkyii (Lauraceae), a new species from Vu Quang National Park, Vietnam, Phytotaxa 527 (3), pp. 215-220 : 215-218

Beilschmiedia danhkyii B.H.Quang, V.H.Nguyen & Tagane , sp. nov. ( Figs. 1 , 2 )

Type: — VIETNAM. Ha Tinh Province: Vu Quang District, Vu Quang National Park , 18°17′20.5″N, 105°21′39.4″E, 109 m a.s.l., 12 December 2020, B.H. Quang, T.D. Binh, H.V. Nguyen, T.C. Toan VQG-VQ 15 [fl. & fr.] (holotype HN!; isotypes KAG!, the herbarium of Vu Quang National Park !) .

Diagnosis: — Similar to Beilschmiedia balansae Lecomte (1913: 108) and B. vidalii Kostermans (1973: 336) of Vietnam in young twigs and terminal buds densely covered with ferruginous hairs, but distinguished from these two by its small tree habit to 8 m tall (vs. 10–28 m tall), more secondary veins (12–15 pairs vs. 3–6 pairs in B. balansae and 4–7 in B. vidalii ) and ellipsoid fruits (vs. globose in B. balansae and pyriform to ovoid in B. vidalii ).

Tree, 5–8 m tall. Bark grayish brown. Terminal buds ovoid, 1–2 mm long, apex acute, densely ferruginous hairy. Twigs densely ferruginous hairy when young, glabrescent, grayish brown, lenticellate. Leaves subopposite; petioles 0.6–1.3 cm long, densely ferruginous hairy when young, glabrescent, slightly sunken adaxially, rounded abaxially; blades elliptic, elliptic-obovate, oblanceolate, 8–19.8 × 3.5–10 cm, thinly coriaceous, adaxial surface glabrous except midrib and secondary veins which are ferruginous hairy, abaxial surface ferruginous hairy, apex acuminate, acumen to 1.2 cm long, margin entire, base cuneate to acute, midrib sunken adaxially, prominent abaxially, secondary veins 12–15 pairs, sunken adaxially, prominent abaxially, tertiary veins scalariform-reticulate, prominent abaxially. Inflorescences axillary, paniculate, 2–3(–5) cm long, (3–)10–15-flowered; rachis densely yellowish brown hairy. Flowers yellow to yellowish green in vivo; pedicel 0.8–3 mm long, densely yellowish brown hairy; bracteoles ovate to linear, 1–2 mm long, densely yellowish brown hairy on both surfaces, caducous. Receptacular tube not distinct, tepals 6, ovate to broadly ovate, 2–3.5 × 1–2 mm, apex acute, sparsely yellowish brown hairy on both surfaces. Stamens 9, 3-whorled, first and second whorls introrse, third whorl extrorse, stamens in third whorl with a pair of glands at base; glands reniform, ca. 0.3 mm long, glabrous; filaments, 0.4–0.7 mm long, hairy near base; anthers 0.4–0.7 mm long, glabrous, 2-celled; staminodes 3, spathulate, ca. 0.8 mm long, glabrous. Ovary ovoid, 0.6–0.8 mm long, glabrous, style ca. 0.2 mm long, stigma capitate, ca. 0.1 mm in diam. Infructescence usually bearing two or three mature fruits. Fruits ellipsoid, 5–8 cm long, 2–4 cm in diam., apex obtuse to rounded, glabrous, green to dark green in vivo, reddish brown in sicco; fruiting stalks 3–5 cm long, thickened, 0.5–0.6 cm in diam.

Additional specimens examined:— VIETNAM. Ha Tinh Province: Vu Quang District, Vu Quang National Park, 18°16′34.2″N, 105°22′14.8″E, 86 m a.s.l., 23 July 2015, Yahara et al. V3459 [ster.] (DLU, FU, the herbarium of Vu Quang National Park); ibid., 18°16′36.3″N, 105°22′08.1″E, 168 m a.s.l., 23 July 2015, Yahara et al. V3497 [young fr.] (DLU, FU, the herbarium of Vu Quang National Park) .

Distribution:— Vietnam (so far known only from Vu Quang National Park).

Habitat:— Beilschmiedia danhkyii grows near streams in primary broad-leaved forest, at elevation from 80 to 170 m. It is associated with Leptostachya wallichii Nees , Ficus pyriformis Hook. & Arn. , Rhamnoneuron balansae (Drake) Gilg , Gironniera subaequalis Planch. , Sloanea sinensis (Hance) Hemsl. , Musa sp. , and Osmunda banksiifolia (C.Presl) Kuhn.

Phenology:— Flowering specimens were collected in December and fruiting in July and December.

Etymology:— The specific epithet danhkyii is named after Mr. Nguyen Danh Ky, the director of the Vu Quang National Park, who made a great contribution for conservation of the primary forests in Vu Quang National Park, and supported us to collect and discover this new species.

Vernacular name:— Chắp danhkyii

Preliminary conservation status:— Critically Endangered (CR). Beilschmiedia danhkyii is known only from three locations in primary broad-leaved evergreen forest in Vu Quang National Park, at elevation between 80 and 170 m, which are 50–1500 m apart each other. The extent of occurrence (EOO) is 0.059 km ² and the area of occupancy (AOO) is 8 km ². Although it is likely to have more subpopulations in the region, the area is considered as a single locality based on IUCN (2021) criteria of the area of occurrence estimated less than 10 km 2. It is locally not a rare species but the number of mature individuals is estimated less than 250 from our field observation. The habitat is located within the protected area of Vu Quang National Park and it is well protected. Given this situation, it is assessed here as Critically Endangered (CR) C2a(ii), following IUCN criteria (2021).

Notes:— Beilschmiedia danhkyii is characterized by ferruginous hairy terminal buds, branchlets and abaxial surface of lamina, subopposite leaves, adaxially impressed midrib and secondary veins, short inflorescence 2–3(–5) cm long, and large ellipsoid fruits 5–8 cm long and 2–4 cm in diam., by which combination it is clearly distinguished from all other Beilschmiedia species known from Indochina. In addition to B. balansae and B. vidalii mentioned in the above diagnosis, B. danhkyii is also similar to B. ferruginea Liu (1932: 107) and B. poilanei Liu (1932: 109) of Vietnam in having densely ferruginous hairy buds, twigs and leaves, though de Kok (2021) excluded the former species from Beilschmiedia due to its inflorescence typical for the genus Dehaasia (type 2 of van der Werff 2001). Beilschmiedia dankyii is distinguished from B. ferruginea by its shorter plant height (5–8 m tall in B. danhkyii vs. 20 m tall in B. ferruginea ), more secondary veins (12–15 pairs vs. 10–12 pairs), and inflorescence short, axillary and paniculate, 2–3(–5) cm long (vs. paniculate-racemose inflorescence with the lateral flowers of the cymes strictly opposite, arising as lateral branches of newly sprouted shoots, (2–) 6–10 cm long); and from B. poilanei by its lamina elliptic, ellipticobovate or oblanceolate and ferruginous hairy on abaxial surface (vs. lanceolate and glabrous). A detailed comparison between these species is shown in Table 1 .

Figures

FIGURE 1. Beilschmiedia danhkyii B.H.Quang, V.H.Nguyen & Tagane. A. Inflorescences. B. Adaxial and abaxial leaf surfaces. C. Portion of inflorescence. D. Flower, side view. E. Flower, top view. F. Inside of flower (some tepals and stamens removed). G. Fruiting branch. H. Fruit longitudinally dissected. From Quang et al. VQG-VQ 15. Photos by Bui Hong Quang.

FIGURE 2. Beilschmiedia danhkyii B.H.Quang, V.H.Nguyen & Tagane.A. Flower, top view. B. Flower with part of receptacle and tepals removed. C. Flower opened out. D–E. Stamens. F. Glands. G. Pistil. From Quang et al. VQG-VQ 15 (HN).