Carpinus wenshanensis Xiaolong Zhou, 2025

Zhou, Xiao-Long & An, Qian-Na, 2025, Carpinus wenshanensis (Betulaceae), a new species from southeast Yunnan, China, PhytoKeys 260, pp. 37-49 : 37-49

Carpinus wenshanensis Xiaolong Zhou sp. nov.

Fig. 1 Chinese name: 文山鹅耳枥

Diagnosis.

Carpinus wenshanensis is morphologically and phylogenetically most closely allied to C. tschonoskii , yet exhibits diagnostic differences in six key characteristics: leaf margin serration (mucronate versus setiform), serrate position on outer bract margin (restricted to the basal half versus extending across both basal and apical halves), fewer serration numbers on outer bract margin (1–3 versus 4–7 serrations per bract), pubescent density of leaf petiole and annual branchlet (nearly glabrous versus sparse or dense), petiole length (1.0–1.7 versus 0.6–1.3 cm), and leaf base morphology (rounded, subrounded, cordate, or subcordate versus rounded-cuneate or cuneate).

Holotype.

China • Yunnan: Bozhushan, Wenshan Prefecture , 23°23'02"N, 103°55'50"E, 2500 m alt., 16 August 2024, X. L. Zhou 2024 WS 01 ( XJU 00050376 A ).

Description.

Trees to 11 m tall; bark gray with shallow vertical fissures. Branchlets gray-brown, glabrous, with prominent white to yellowish-white lenticels. Leaves: petiole 1.0– 1.7 cm, nearly glabrous; blade elliptic, oblong, or ovate-lanceolate, 5.4–9.2 × 2.8–4.2 cm (length-to-width ratio 1.9–2.8); abaxial surface sparsely villous along veins, bearded in axils of lateral veins, adaxial surface glabrous; base rounded, subrounded, cordate, or subcordate; apex acute, acuminate, or caudate; margin irregularly or doubly mucronate-serrate; lateral veins 11–14 pairs. Inflorescences 5.5–8.5 × 3.0– 4.5 cm; peduncle 1.5–3.0 cm, sparsely villous. Bracts semiovate- to ovate-lanceolate, loosely imbricate, 2.2–3.1 × 0.7–1.0 cm, adaxially sparsely pubescent; outer margin with 1–3 serrations restricted to the basal half, lacking basal lobe; inner margin entire, bearing an inflexed basal lobe (1.0–2.0 mm); apex acute or acuminate; primary veins 3–4 (excluding inflexed lobe), venation prominent. Nutlets broadly ovoid, 4.0–5.0 × 3.5–4.5 mm, sparsely to densely pubescent, villous at apex, sparsely resinous-glandular, prominently ribbed.

Etymology.

To date, this hornbeam is known only from a single population in Wenshan Prefecture. Given its apparently restricted endemic status and limited distribution, we have chosen the specific epithet wenshanensis to reflect its geographic origin.

Phenology.

Flowering time unknown, and fruiting time from June to September.

Habitat, distribution and conservation.

During a six-day survey of Bozhushan and adjacent areas in Wenshan Prefecture, we documented hornbeam distributions but failed to locate the additional population of C. wenshanensis . This newly described species occupies higher elevations than sympatric congeners (e. g., C. fargesii ). The sole known population comprises a single reproductive adult (11 m tall) and three seedlings (0.5–2.5 m) in a roadside secondary forest. Notably, the mature tree produces abundant fruit (Fig. 1 ), suggesting either: (1) self-pollination capability, or (2) pollen contribution from undetected conspecifics. This reproductive ecology requires further study. Following IUCN Red List criteria (2016), we recommend classifying C. wenshanensis as Critically Endangered (CR) due to extremely limited distribution (single location) and minimal population size (1 reproductive individual). However, its occurrence within a protected area offers some conservation assurance. Expanded surveys are needed to assess whether additional populations exist.

Additional specimens examined for this new hornbeam species.

China • Yunnan: Wenshan Prefecture , 23°23'02"N, 103°55'50"E, 2500 m alt., 16 August 2024, X. L. Zhou 2024 WS 02 ( XJU 00050376 B ) and X. L. Zhou 2024 WS 03 ( XJU 00050376 C ) .

Figures

Figure 1. Carpinus wenshanensis Xiaolong Zhou. A. The mature tree; B. Several branchlets with infructescences and leaves; C. Leaf; D. A representative infructescence; E. Nutlet and the bract with a prominent lobe at the base of inner margin. All red bars are one centimeter long.