Lithocarpus dahuensis H.X.Su, Miao Zhang & B.Hua Chen, 2023

Zhang, Miao, Zhang, Xiao-Hui, Shi, Shi & Chen, Bing-Hua, 2023, Lithocarpus dahuensis (Fagaceae), a new species from Fujian Province based on morphology and genomic data, PhytoKeys 222, pp. 1-18 : 1

Lithocarpus dahuensis H.X.Su, Miao Zhang & B.Hua Chen sp. nov.

Figs 4A-C, F-H , 5 , 6A, D-J , 7

Diagnosis.

Lithocarpus dahuensis differs from L. konishii by having an oblanceolate leaf blade with 7-10 pairs of acute teeth on the leaf margin from the second to third lateral veins above the leaf base (compared to 3-6 pairs of obtuse teeth for L. konishii ), and its lateral veins are numerous and dense, reaching up to 15 pairs; it has 4-10 female flowers, borne singly in the lower part of staminate catkins; the cupules are smaller, encrusting up to 1/4-1/3 of the nut, and the nut is only half as high as those of L. konishii (1.4-1.8 vs. 1.8-2.4 cm) (Table 3 ).

Type.

China. Fujian Province, Fuzhou City, Minhou County, Dahu town , Niumu Mountain , forest margins, 26°25'N, 119°3'E, elevation 1035 m, 10 Sep. 2017, B. Hua Chen CBH02292 (Holotype, FNU, barcode FNU0039021; Isotypes, FNU, barcode FNU0038769) .

Description.

Trees usually less than 8 m tall, evergreen. Branchlets densely grayish yellow tomentose, soon glabrescent. Bud scales compact, densely covered with grayish yellow silky short hairs. Leaf blade oblanceolate or ovate-elliptic, 3.7-9.8 × 1.1-3.2 cm, leathery, concolorous, apex acuminate to caudate, ca. 9 mm long, base cuneate and inaequilateral, margin with 7-10 acute teeth except basally entire, abaxially with tufts of hairs along veins; midvein adaxially puberulent; secondary veins 7-16 on each side of midvein, adaxially slightly impressed; tertiary veins slender, evident. Petiole 0.5-1.3 cm, tomentose, soon glabrescent. Rachis of inflorescences densely tawny tomentose. Inflorescences male, or androgynous, 2-6, in leaf axils toward base of branchlets or in a dense paniculate cluster on subterminal shoots, erect; rachis of male inflorescences, 5.6 cm long; flowers usually 3 in dichasial clusters; perianth 6-lobed; stamens 12. Female flowers 4-11, borne on basal part of androgynous inflorescences, perianth 6-lobed, styles 3, 3 mm. Infructescences 1.4-4.3 cm; rachis 4.5 mm thick, glabrescent, lenticellate. Cupule usually 1(or in clusters of 2-3-(4)), saucer-shaped, 4.6-7.4 mm × 2.2-2.7 cm, enclosing ca. 1/4-1/3 of nut, wall 1.0-2.5 mm thick; bracts imbricate, broadly triangular, covered with grayish brown, shortly tomentose hairs, midvein ridged. Nut depressed globose, 1.0-1.9 × 1.5-2.6 cm, glabrous, apex flat, wall 3.3-6.9 mm thick and horny; scar 1.5-1.9 cm in diam., margin concave but center convex.

Distribution and habitat.

Lithocarpus dahuensis is only found in Dahu town, Minhou County, Fujian, China (Fig. 8 ), where it grows in valleys of subtropical evergreen broad-leaved forest. Many other plants grow in the surrounding habitat, whose tree layer includes Castanopsis eyrei (Champ. & Benth.) Tutcher ( Fagaceae ), Quercus sessilifolia Blume ( Fagaceae ), Schima superba Gardner & Champ. ( Theaceae ), Semiliquidambar chingii (F.P.Metcalf) H.T.Chang ( Altingiaceae ), Ilex elmerrilliana S.Y.Hu ( Aquifoliaceae ), Dendropanax dentiger (Harms) Merr. ( Araliaceae ) and others; the shrub layer includes Rhododendron ovatum (Lindl.) Planch. ( Ericaceae ), Syzygium buxifolium Hook. & Arn. ( Myrtaceae ), Lindera aggregata (Sims) Kosterm. ( Lauraceae ), Symplocos stellaris Brand ( Symplocaceae ), Ardisia crispa (Thunb.) A. DC. ( Primulaceae ), Ilex asprella (Hook. & Arn.) Champ. ex Benth. ( Aquifoliaceae ), Cleyera japonica Thunb. ( Pentaphylacaceae ), Pyrularia edulis (Wall.) A. DC. ( Santalaceae ), Oligostachyum oedogonatum (Z.P. Wang & G.H.Ye) Q.F.Zhang et K.F.Huan ( Poaceae ), Ilex serrata Thunb. ( Aquifoliaceae ), Rubus buergeri Miq.( Rosaceae ), Rubus impressinervus F.P.Metcalf ( Rosaceae ), Ligustrum sinense Lour. ( Oleaceae ), Clerodendrum cyrtophyllum Turcz. ( Lamiaceae ), Erythroxylum sinense Y.C.Wu ( Erythroxylaceae ) and others; the vegetation layer includes Dicranopteris pedata (Hout.) Nakaike ( Gleicheniaceae ), Hypolepis punctata (Thunb.) Mett. ( Dennstaedtiaceae ), Diplopterygium chinense (Rosenst.) De Vol ( Gleicheniaceae ), Woodwardia japonica (L. f.) Sm. ( Blechnaceae ), Lobelia sessilifolia Lamb. ( Campanulaceae ), Oenanthe linearis Wall. & DC. ( Apiaceae ), Melastoma dodecandrum Lour. ( Melastomataceae ), Carex perakensis C.B.Clarke ( Cyperaceae ), Anoectochilus roxburghii (Wall.) Lindl. ( Orchidaceae ), Tainia dunnii Rolfe ( Orchidaceae ) and others; the interlayer plants include Trachelospermum brevistylum Hand.-Mazz. ( Apocynaceae ) and others.

Phynology.

Florescence May to June, fruiting season September to October of the following year.

Etymology.

Chinese name: 大湖柯 (da hu ke). The epithet dahuensis (大湖) refers to Dahu town, Minhou County, Fujian Province where this new species was found.

Taxonomic notes.

The following morphological characteristics were used to classify the species, including the acute teethed leaf blade margins, a concave nut scar, and cupules that do not completely enclose the nut. There are four other plants share similar characteristics with L. dahuensis , including cupule encrustation (the cupule base is sessile, encasing the base of the nut or about half of it) and a fruit umbilicus (the surrounding margin of the fruit umbilicus is clearly concave), the differences between which are shown in the key.

Conservation status.

During our fieldwork from 2017 to 2022, fruit-bearing large trees of Lithocarpus dahuensis were only found in the landscape forest of the Xuefeng village valley, Dahu town, Minhou County, Fujian Province, China. They were also found in the surrounding secondary coniferous and broad-leaved mixed forest, but these were mostly small trees that sprouted after the large trees were felled and did not bear fruit. As the location was discovered to be the only known position, we suggest its placement in the Data Deficient category of IUCN (2022).

Figures

Figure 4. Lithocarpus dahuensis H. X. Su, Miao Zhang & B. Hua Chen, sp. nov. A fruiting stem with mature cupule B, C adaxial and abaxial side of mature leaf, respectively D, E adaxial and abaxial side of mature leaf of Lithocarpus konishii (Hayata) Hayata, respectively (photographed by Shi Shi) F bark G lower young leaf surface, showing abaxially hairy H petiole and buds, showing grayish yellow short hairs. Scale bars: 1 cm (B-E); 1 mm (G); 2 mm (H).

Figure 5. Lithocarpus dahuensis H. X. Su, Miao Zhang & B. Hua Chen, sp. nov. A branch with mature male and androgynous inflorescences B male inflorescences C androgynous, showing female flowers borne on basal part of inflorescences (red arrows) and male flowers (white arrows) D male flower F female flower. Scale bars: 5 mm (B, C); 2 mm (D, E).

Figure 6. Lithocarpus dahuensis H. X. Su, Miao Zhang & B. Hua Chen, sp. nov. A branch with mature cupule a infructescence, showing mature cupule enclosing 1 / 4 of nut B, C Lithocarpus konishii (Hayata) Hayata (photographed by Shi Shi and Jin-Long Zhang from Hainan and HongKong, respectively) D vertical section of mature fruit E-G outside, inside and side view of the cupule, respectively H-J top, side and bottom view of mature nut, respectively. Scale bars: 2 cm (A); 1 cm (a); 5 mm (D-J).

Figure 7. Lithocarpus dahuensis H. X. Su, Miao Zhang & B. Hua Chen, sp. nov. A fruiting branch with mature cupule B abaxial side of mature leaf C female flower D male flower E, F outside and inside view of the cupule, respectively G infructescence, mature cupule usually solitary H mature cupule enclosing 1 / 4 of nut I vertical section of mature fruit J-L side, top and bottom view of mature nut, respectively. Scale bars: 1 cm (A, B, E-I); 1 mm (C, D).

Figure 8. Distribution of Lithocarpus dahuensis and L. konishii in China. Legend: (red star) L. dahuensis, (blue triangle) L. konishii.