Litsea rubrobrunnea 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 : 15-18

11. Litsea rubrobrunnea de Kok , sp. nov.

( Figs 11 ; 12 )

DIAGNOSIS. — This species differs from its close relative Litsea monopetala (Roxb.) Pers. by having leaves with an acute apex and 10-13 pairs of secondary nerves (while L. monopetala has leaves with an obtuse acute to acuminate apex and 6-11 pairs of secondary nerves); petioles which are swollen and 8-11 mm long (while L. monopetala has petioles which are slender and 10-25 mm long). —

TYPE SPECIMEN. — [ Vietnam] près Tourane , 16°4’18.372”N, 108°9’1.368”E, 10.VIII.1923, Poilane 7829 (holo-, P [ P01976151 ]).

DISTRIBUTION. — Vietnam (see Fig. 12 ).

ECOLOGY. — Growing in lowland and mountain forest, sometimes over limestone, between 500-1800 m altitude. Flowering between December to April; fruiting from August to March.

CONSERVATION ASSESSMENT. — Vulnerable (VU B2ab(ii,iii)). This species is only known from six localities. An analysis of the Extent of Occurrence (EOO) gives an assessment of Least Concern and the Area of Occupancy (AOO) suggests an IUCN Conservation Assessment of Vulnerable. Given that it is known from only six populations and has small area of occupancy as well as the intensive logging and landscape modification that has occurred in the region during the last 50 years, this species must be considered Vulnerable.

ADDITIONAL COLLECTIONS SEEN. — Vietnam. Thua Thien-Hue: Nui Back Ma , près de Hu ế, 16°10’0.984”N, 107°49’58.008”E, 20.IV.1939, Poilane 29853 ( P02132127 ) ; Quang Tri: Massif de Dong Che , 16°37’58.8”N, 106°55’58.8”E, 22.VIII.1924, Poilane 11271 ( P02132139 ) ; Quang Nam: près de village Moi de Go-oi , 24.II.1941, Poilane 31548 ( P) ; Đà N ẵng: Ba-Na, près Tourane , 11°22’39.648”N, 108°50’36.996”E, 27.II.1939, Poilane 29117 ( P02035874 ) ; Lào Cai: village de Tien Chua, nord de Lai Chau, 22°24’51.732”N, 103°26’57.264”E, 12.IV.1936, Poilane 25728 ( P01976047 ) .

DESCRIPTION

Tree 5-10 m tall, dbh 10-33 cm. Twigs slender 2.6-4.2 mm thick, rounded in cross-section, sparsely hairy when young, glabrescent; hairs yellowish, appressed; terminal leaf bud ovoid, c. 2 mm long, apex acute, velutinous. Leaves alternate, drying brown reddish; blade elliptic to lanceolate, 12-16 × 4.5-6 cm, apex acute, base cuneate, blade leathery, penninerved, secondary nerves 10-13 pairs, curved near margin and brochidodromous, tertiary nerves scalariformreticulate; upper surface glabrous, sometimes densely hairy on midrib, midrib and secondary nerves sunken, tertiary nerves distinct; lower surface sparsely hairy, often more densely hairy on major veins, midrib and secondary nerves raised, tertiary nerves distinct; petiole half-terete, 8-11 mm long, swollen, densely hairy.

Inflorescences in leaf axils, 4-8 mm long, in clusters of umbels, glabrous to sparsely hairy; hairs yellowish, appressed. Flowers unknown.

Fruit ellipsoid, 14-18 × 6.5-9.7 mm, apex rounded, smooth, glabrous;cupule woody,4.5-5× 2.9-4mm,margin entire,glabrous, surface warty; stalk not swollen, c. 2.3 mm thick (see Fig. 11 ).

NOTES

Flowers are unknown for this new species, which is problematic for its generic placement. However, its other characters fit morphologically (like the inflorescence shape and cupule) very well in Litsea , and I have decided to place it here.

Figures

FIG. 11. — Plate of Listea rubrobrunnea de Kok, sp. nov.: A, twig with leaves and infructescence; B, infructescence with fruit; C, detail of leaf under surface. All from Poilane 29117 (P02035874). Drawing by Giulia Iaconelli. Scale bars: A, 4 cm; B, 2 cm; C, 1.5 cm.

FIG. 12. — Distribution of Litsea rubrobrunnea de Kok, sp. nov. (), Litsea salmonea A.Chev. ex de Kok, sp. nov. (), Machilus coriacea A.Chev. ex de Kok, sp. nov. (), Neocinnamomum huongsonensis Kim Dao, sp. nov. () and Phoebe petelotii Kosterm. ex de Kok, sp. nov. ().