Carpinus langaoensis Z. Qiang Lu & J. Quan Liu, 2017

Lu, Zhiqiang, Liu, Siyu, Yang, Xiaoyue, Liang, Qianlong, Yang, Yongzhi, Zhang, Dan, Milne, Richard & Liu, Jianquan, 2017, Carpinus langaoensis (Betulaceae), a new hornbeam species from the Daba Mountains in Shaanxi, China, Phytotaxa 295 (2), pp. 185-193 : 191-192

Carpinus langaoensis Z. Qiang Lu & J. Quan Liu , sp. nov. ( Fig. 1 & 2 )

Carpinus langaoensis is similar to C. tientaiensis W. C. Cheng and C. mianningensis Yi by the presence of the long bract with lobes at bases of both inner and outer margins and large glabrescent nutlet, but distinct from both by the dense pubescence on the abaxial leaf and the long infructescence bract.

Type: China. Shaanxi: Langao County, Hengxi Township , 108°48’E, 32°08’N, 1170m a.s.l., on the forest edge near the stream, 28 Jul 2016, Z. Q. Lu 2016 LZQ029 (holotype, LZU; isotype, LZU) .

Etymology:— Due to its endemism and extremely narrow distribution range, we named this new species for the County where it is distributed.

Description:— Tree to 20 m tall; bark gray, smooth. Branchlets yellow-brown, densely yellow pubescent, glabrescent in the second year. Petiole 7–15 mm, densely pubescent; leaf blade elliptic, ovate-elliptic or ovate, 5–12 cm × 3–6 cm, subcoriaceous, abaxially densely white-pubescent, adaxially glabrous, base commonly subrounded, rarely subcordate, margin doubly and obtusely shortly serrate, apex acute, lateral veins 11–16 on each side of midvein. Female inflorescence ca. 10 cm; peduncle ca. 2 cm, densely pubescent; bracts loosely overlapping, 3.5–3.9 cm × 7–10 mm, glabrescent except sparsely pubescent along veins, 3-lobed, middle lobe falcate-oblong or falcate–lanceolate, outer margin entire or 1–2 undulate-serrate close to base, with triangular and flattened basal lobe 2–4 mm, inner margin entire, with inflexed basal lobe 4–5 mm, apex obtuse, rarely acute, veins 5–8, reticulate veins present. Nutlet broadly ovoid or triangular–ovoid, 6–7 mm × 4.5–5.5 mm, glabrescent except pubescent at apex, 6–8-ribbed. Fl. Mar–Apr, fr. May–Aug.

Distribution and conservation: —Only one small population was found at the specific site for this new tree species (108°48’E, 32°08’N, 1170m) from the Langao County. It grows on the forest edge near the stream. All found trees are sporadically distributed in an area less than 0.5 km 2. Mature flowering and fruiting trees (12 trees) are approximately 10–20 m tall, and the young trees (37 trees) are from 2 to 7 m (mostly 5–7m). According to the IUCN categories and criteria ( IUCN 2016), this species fits the criteria for “Critically Endangered” (CR), and should be classified as such. Hence, it will be necessary to pay great attention to the conservation of this new species. The presence of many juveniles provides the possibility to expand the adult population quite quickly, if appropriate management is applied to the site.

Figures

FIGURE 1. Carpinus langaoensis Z.Qiang Lu & J. Quan Liu was drawn from Z.Q. Lu 2016LZQ029 (LZU).

FIGURE 2.A–F.Carpinus langaoensis Z.Qiang Lu& J.Quan Liu.A.The whole plant andhabitat.B. Branch.C.Leaves.D. Infructescence. E. Bracts.