Beilschmiedia bidoupensis Komada, Tagane & Yahara, 2022

Komada, Natsuki, Tagane, Shuichiro, Matsuo, Ayumi, Ngoc, Nguyen Van, Binh, Hoang Thi, Nagahama, Ai, Cuong, Truong Quang & Yahara, Tetsukazu, 2022, Beilschmiedia bidoupensis (Lauraceae), a new species from Bidoup-Nui Ba National Park, southern highland of Vietnam, Phytotaxa 559 (3), pp. 285-292 : 287-290

Beilschmiedia bidoupensis Komada, Tagane & Yahara , sp. nov.

Figs. 2 & 3 .

Type: — VIETNAM. Lam Dong Province, Bidoup-Nui Ba National Park , evergreen forest, 12°09′52.95″N, 108°32′00.38″E, elev. 1698 m, 24 February 2016, fl., Tagane et al. V4329 (holotype KYO!, isotype DLU!) .

Diagnosis: —Similar to Beilschmiedia turbinata Liu & Yang (2013: 2) in having small hairy terminal buds without coriaceous scales, alternate (rarely subopposite) leaves, glabrous and elliptic leaf blade, and fruits larger than 3 cm both in length and diameter, and brown and furfuraceous surface. However, Beilschmiedia bidoupensis is distinguished from B. turbinata by having smaller terminal buds [(1.5–) 2.5–3 mm long vs. 4–5 mm], shorter petioles (0.8–1.1 cm long vs. 1.4–2 cm), depressed globose to transversely ellipsoidal fruits that are 3–3.6 cm high, 3.7–6 cm wide, 3.5–4 cm thick, and are pale brown, not verrucose but asperously furfuraceous and without irregular longitudinal ridges on the surface (vs. ellipsoid, 5.4–7.2 × 3.8–4.6 cm, the surface ferrugineous-furfuraceous and with 16–20 irregular longitudinal ridges), and presence of glands on the third whorl of stamens (vs. absent).

Evergreen tree up to 11 m tall, DBH 12 cm; bark grayish brown, smooth. Young twigs 1.1–2.5 mm in diameter, glabrous and smooth, shallowly 2-angled, greenish in vivo, dark brown in sicco, old twigs grayish to pale brown in sicco, lenticellate. Terminal buds lanceolate, (1.5–) 2.5–3 mm long, densely covered with whitish brown silky hairs, without scales. Leaves alternate, evenly arranged with 1–4 cm interval, or rarely sub-opposite; blades elliptic, 8–11(–16) × (3.5‒)4–5.5(–6.5) cm, thinly coriaceous, dark brown adaxially, dark greenish brown to dark purplish brown abaxially, glabrous and not glandular punctate on both surfaces, apex acuminate, acumen 0.8–1.5(–2) cm long, base cuneate or slightly decurrent, sometimes slightly oblique, margins entire, flat or slightly undulate, midrib flat to slightly sunken adaxially, prominent abaxially, secondary veins brochidodromous, (6–)7–9(–10) pairs, flat to slightly prominent on both surfaces, tertiary veins reticulate, prominent on both surfaces and fine veins conspicuously foveolate in sicco; petiole 0.8–1.1 cm long, glabrous, concave adaxially, rounded abaxially. Inflorescences axillary, paniculate, 1.5–3.8 cm long, 15–46-flowered, peduncle 0.3–1 cm long, peduncle and rachis sparsely pubescent; bracts at base of each rachis, lanceolate to orbicular, 1–1.3 mm long, apex acute, margin entire and ciliate, pubescent on both surfaces, caducous; bracteoles lanceolate, ca. 0.5 mm long, apex acute, margin entire and ciliate, pubescent on both surfaces, caducous; pedicel 1.5–2 mm long, terete, pubescent. Flowers yellowish green, ca. 2.5 mm in diameter. Tepals 6, equal, ovatenavicular, ca. 1.2 × 1 mm, pubescent adaxially, glabrous or sparsely pubescent abaxially. Stamens 9, 3-whorled, ca. 0.5 mm diameter, first and second whorl introrse, third whorl extrorse, stamens in third whorl with a pair of glands at base, glands globose, ca. 0.3 mm in diameter; filaments ca. 0.2 mm long, with translucent hairs; anthers 0.3 × 0.3–0.5 mm, apex obtuse to truncate, pubescent only at base and scarcely verrucose at upper part. Staminodes 3, spathulate to sagittate, 0.4–0.5 × 0.2–0.3 mm, pubescent at lower half. Ovary ovoid, ca. 0.6 mm long, 0.5 mm in diameter, glabrous; Style ca. 0.3 mm long, terete, glabrous, stigma capitate. Fruits depressed globose to transversely ellipsoidal, 3–3.6 cm high, 3.7–6 cm wide, 3.5–4 cm thick, pale brown, apex rounded, not verrucose but asperously furfuraceous on the surface; fruiting pedicel ca. 4 mm long, 2 mm in diameter, rusty brown, glabrous.

Other specimens examined:— VIETNAM. Lam Dong Province, Bidoup-Nui Ba National Park: Dung Iar Gieng (spelled as “Dinh Gia Rieng” on the labels), 12º09′27.6″N, 108º32′06.6″E, 1602 m, 24 March 2018, ster., Yahara et al. V7759 (DLU, FU); 12°09′49.18″N, 108°32′12.66″E, 1634 m, 25 December 2018, fl., Yahara et al. V9667 (DLU, FU, KAG127417) ; same locality, 12º09′36.61″N, 108º32′11.16″E, 1656 m, 14 June 2018, ster., Yahara et al. V8195 (DLU, FU) ; same locality, 16 June 2018, ster., Yahara et al. V8423 (DLU, FU) ; same locality, 26 September 2019, fr., Tagane et al. V9362 (DLU, FU, KAG127642) , same locality, 21 April 2019, fl., Yahara et al. V9813 (DLU, FU) ; same locality, 19 July 2019, fr., Yahara et al. V10169 (DLU, FU) .

Distribution:— Vietnam (so far known only from Bidoup-Nui Ba National Park).

Habitat and phenology: Beilschmiedia bidoupensis is locally common in a lower montane broad-leaved evergreen forest at an elevation between 1602 and 1698 m in Bidoup-Nui Ba National Park. Flowering specimens were collected in December, February and April, and fruiting specimens in July and September.

Etymology:— The species epithet refers to the Bidoup-Nui Ba National Park, where this species was first collected.

Preliminary conservation status: —Vulnerable (VU) (IUCN 2012). At present, the population of Beilschmiedia bidopuensis is known only in an evergreen forest stand at the Dung Iar Gieng area in Bidoup-Nui Ba National Park and the species has the EOO of 0.178 km 2 and the AOO of 8 km 2 both below the Critically Endangered (CR) threshold; however, the locality is within a protected area and deforestation is unlikely to occur. In the forest, we found and monitored 14 trees taller than 4 m, in a plot of 50 m × 50 m, among which three flowered during our censuses from 2018 to 2019. In our intensive field observation from 2016 to 2019, the number of mature individuals of B. bidopuensis is probably about 100 times our record (ca. 300 individuals). Given this situation, we qualify this species as VU according to the IUCN criterion D1 & 2 (IUCN 2012).

GenBank accession number: — Yahara et al. V10169 : LC712396 (ITS1) , LC712397 (ITS2) , LC712398 (psbAtrnH-R1) , LC712399 (psbA-trnH-R2) , LC712400 (trnL-R1) , LC712401 (trnL-R2).

Notes: — Beilschmiedia bidoupensis can be distinguished from the other species of Beilschmiedia in Vietnam and surrounding countries by its distinctive morphological characters, namely, lanceolate terminal buds covered with whitish brown hairs, glabrous twigs and leaves, alternate elliptic leaves with acuminate apex leaves that are evenly arranged on twigs, and depressed globose to transversely ellipsoidal fruits with pale brown, not verrucose but furfuraceous surface.

Particularly, hairy terminal buds, predominantly alternate leaves, and depressed globose to transversely ellipsoidal furfuraceous fruits are good diagnostic traits from the other species of Beilschmiedia in the region and only B. turbinata , which was recently described from southern China, shares some of these traits. However, B. bidoupensis is distinguished from B. turbinata by smaller terminal buds, shorter petiole, pale brown depressed globose to transversely ellipsoidal fruits without longitudinal ridges on the surface, and presence of glands on the third whorl of stamens. Beilschmiedia purpurascens Li in Lee et al. (1979: 63) and B. macropoda Allen (1942: 452) , both from China, also share some characters, namely hairy terminal buds, leaves not clustered at apex, and not verrucose, brown furfuraceous fruits. However, B. bidoupensis readily is distinguished from B. purpurascens by lanceolate terminal naked buds (vs. globular terminal buds with coriaceous scales) and depressed globose to transversely ellipsoidal fruits (vs. ellipsoid) and from B. macropoda by predominantly alternate leaves (vs. opposite or subopposite leaf arrangement).

Figures

FIGURE 2. Beilschmiedia bidoupensis Komada, Tagane & Yahara. A. Twig with inflorescence; B. Bud; C. Detail of abaxial leaf surface showing finely reticulated tertiary veins; D. Portion of inflorescence; E. Flower with some tepals and stamens in a first (outermost) whorl removed; F. Pistil; G. Staminode; H. Stamen and basal glands in third (innermost) whorl (extrorse); I. Stamen in second whorl (introrse); J. Stamen in first whorl (introrse); K. Fruit; L. Vertical section of fruit. MaterialsA–J from Tagane et al. V4329 (KYO), K–L from Tagane et al. V9362 (KYO).

FIGURE 3. Beilschmiedia bidoupensis Komada, Tagane & Yahara. A. Twig with inflorescence; B. Abaxial leaf surface; C. Shoot apex showing buds; D. Inflorescence; E–F. Flowers; G–H. Fruits; I. Longitudinal section of fruit. A, D taken on 25 December 2018 (from V9667); B taken on 16 June 2018 (from V8423); C taken on 14 June 2018 (from V8195); E & F taken on 24 February. 2016 (from V4329); G–I taken on 26 September 2018 (from V9362). Scale bar on G = 5 cm.