Litsea nhatrangensis de Kok, 2023

De Kok, Rogier P. J., 2023, The Lauraceae Juss. of Indo-China: fifteen new species, four new combinations and two neotypifications, Adansonia (3) 45 (1), pp. 1-25 : 15

10. Litsea nhatrangensis de Kok , sp. nov.

( Figs 7 ; 10 )

Litsea robusta sensu Nguyén Kim Đào , Lauraceae in Checklist of Plant Species of Vietnam 2: 98 (2003); Nguyén Kim Đào, Flora of Vietnam 20: 402 (2017).

DIAGNOSIS. — This species differs from its close relative Litsea grandifolia Lecomte by having leaves with 11-15 pairs of secondary nerves, a midrib and secondary nerves which are raised above and tertiary nerves that are distinct on the lower surface (while L. grandifolia has leaves with 6-8 pairs of secondary nerves, a midrib and secondary nerves which are sunken above and tertiary nerves that are indistinct on the lower surface); petioles which are 23-55 mm long (while L. grandifolia has petioles 9-11 mm long); fruits that are globose, 20-25 × 20-22 mm with a cupule 18-20 × 9-10 mm and a swollen stalk (5-6 mm thick) (while L. grandifolia has fruits that are ellipsoid, 8.8-15 × 5.6-9 mm with a cupule 7-8.3 × 7.3-12 mm and a slender stalk (c. 1.3 mm thick).

TYPE SPECIMEN. — Vietnam, Nha Trang , 12°40’59.988”N, 108°58’0.012”E, alt. 450 m, 4.IX.1922, Poilane 5019 (holo-, P [ P04456803 ]; iso-, P [ P04450136 , P04456748 ].

VERNACULAR NAME. — Vietnamese: Toc poc (Poilane 5019).

DISTRIBUTION. — Laos and Vietnam (see Fig. 7 ).

ECOLOGY. — Growing in forest over limestone, between 300-450 m altitude. Flowering in April; fruiting from February to December.

CONSERVATION ASSESSMENT. — Endangered (EN B1ab(i,iii), B2ab(ii,iii)). This species is only known from four collections representing four localities in Vietnam and Laos. An analysis of the Extent of Occurrence (EOO) and Area of Occupancy (AOO) gives an IUCN Conservation Assessment of Endangered.

ADDITIONAL COLLECTIONS SEEN. — Vietnam. Lang Son: entre Dong Mô et Van Linh, 21°48’43.992”N, 106°42’42.984”E, 28.IV.1938, Pételot 6373 ( P01976196 ); Ninh Binh: Cuc Phuong National Park , 12.III.2007, Nguyen et al. HNK-1468 (K) .

Laos. Louang Prabang, Pac Bae , 19°45’2.34”N, 102°16’56.388”E, alt. c. 300-400 m, 23.III.1932, Poilane 20485 ( P02011178 , P02035910 ) .

DESCRIPTION

Tree 5-18 m tall, dbh 15-43 cm. Twigs stout, 6.3-7.4 mm thick, rounded in cross-section, glabrous; terminal leaf bud unknown. Leaves alternate; blade lanceolate, 18-45 × 10- 16 cm, apex acute, sometimes emarginate, base cuneate, blade stiff-leathery, penninerved, secondary nerves 11-15 pairs, curving and looping near margin, tertiary nerves scalariform-reticulate; upper surface glabrous, midrib and secondary nerves raised, tertiary nerves distinct; lower surface glabrous, midrib and secondary nerves raised, tertiary nerves distinct; petiole half-terete, 23-55 mm long, swollen, glabrous.

Inflorescences cauliflorous or in leaf axils, 15-30 mm long, in clusters of umbels, densely hairy; bracts 4, 5-6.3 × 4.5-5 mm, apex acute, velutinous. Flowers: male flowers: perianth lobes 3.4-4.6 × 0.9-1.7 mm, apex rounded to acute, sparsely hairy outside, glabrous inside; stamens 3.9-4.8 mm long, sparsely hairy; female flowers: perianth lobes lanceolate, 2-2.5 × 0.6-0.8 mm, apex acute, glabrous.

Fruits globose, 20-25 × 20-22 mm, apex rounded, smooth, glabrous; cupule shallow, 18-20 × 9-10 mm, margin entire, warty; stalk slender, 6-8.5 × 5-6 mm (see Fig. 10 ).

Figures

FIG. 7. — Distribution of Cinnamomum petelotii Kosterm.ex de Kok,sp.nov.(), Cinnamomum scalarinervium Kosterm.ex de Kok,sp.nov.(), Litsea banaensis de Kok,sp. nov. (), Litsea honbaensis de Kok, sp. nov.() and Litsea nhatrangensis de Kok, sp. nov. ().

FIG. 10. — Plate of Litsea nhatrangensis de Kok, sp. nov.: A, twig with leaves; B, infructescence with fruit; C, detail of leaf under surface. All from Poilane 5019 (P04456803). Drawing by Giulia Iaconelli. Scale bars: A, 5 cm; B, 2 cm; C, 1 cm.