Piper hongheense W.J. Zhao, C.Y. Hao & N.H. Xia, 2025

Fan, Rui, Zhao, Wen-Jing, Su, Fan, Li, Yang, Ji, Xun-Zhi, Su, Bao-Fen, Xia, Nian-He & Hao, Chao-Yun, 2025, Piper hongheense (Piperaceae), a new species from Yunnan, China, Phytotaxa 697 (1), pp. 129-137 : 130-131

Piper hongheense W.J. Zhao, C.Y. Hao & N.H. Xia , sp. nov. ( Figs. 1–2 )

Type: — CHINA. Yunnan: Pingbian County, Daweishan National Natural Reserve, tropical montane moist forests, elevation 1424 m, 23°00'07"N, 103°41'53"E, 19 May 2023, C. Y. Hao et al. Hao0159 (holotype IBSC 0918555!, isotypes IBSC 0918556, IBSC 0918557!).

Erect subshrub, 0.7–1 m high, aromatic, dioecious. Stem greenish, terete, 3–4 mm in diameter, young branchlet sparsely puberulent, glabrescent, finely striate when dry, swollen at node. Leaf dimorphism present, prophyll 1–2 cm long. Sympodial leaf membranous to chartaceous, finely glandular, oblong-lanceolate to lanceolate, 10–16 cm × 2.5–4 cm, base subequilaterally truncate to oblique, one side rounded, the other tapered and acute; apex acutely acuminate to long acuminate, adaxially green and glabrous, abaxially pale greenish and sparsely puberulent on veins; petioles glabrous, 5–7 mm long; venation plinerved, veins 5–9, reticulate, uppermost distal pair of secondary veins alternate, arising 1–3 cm above base, reaching leaf apex, others basal. Monopodial leaf exhibits morphological similarities to sympodial leaf, with the primary distinction being that the base of monopodial leaf is predominantly symmetrical. Inflorescence a pedunculate spike, leaf-opposed, solitary, pendulous, cylindrical, white. Male inflorescence delicate, 10–15 cm × 2–3 mm; peduncle slender, 3–3.5 cm long, glabrous; axis glabrous; bracts imbricate, white, subcircular, 1.5–2 mm wide, base often concave, apex slightly protruding, peltate, stalk 0.8–1 mm long; stamens 2; filaments marginally longer than anthers, anthers ovoid to globose, 2-locular. Female inflorescences shorter than male ones, 4–8 cm × 3–5 mm; peduncle and bracts as in male spikes; rachis sparsely pubescent; ovary ovoid, distinct; stigmas 3 or 4. Infructescence pendulous, 5–10 × 0.5–0.8 cm, glabrous, cylindrical, white. Fruit single–seeded berry, ± 1.5 mm in diam., ovoid to globose, connate on rachis, glabrous, distinct; floral bracts persistent, white; seed pale brown, ovoid, ± 1 mm in diam., smooth.

Phenology:— Flowering from March to June; fruiting from July to November.

Etymology:— The epithet refers to its distribution, Honghe Prefecture in Yunnan, China.

Distribution and habitat:— Piper hongheense is currently known only from its type locality in Pingbian county, Honghe Prefecture in Yunnan ( Fig. 3), in wet tropical montane forest, at elevations of 1000–1600 m. Nevertheless, considering that this new species thrives in the shadow of wet tropical montane forests in Jinping, a region adjacent to Tinh Ha Giang and Tihn Lao Cai in Vietnam, it is highly likely that the species is also present in Vietnam.

Taxonomic affinities:— The new species is morphologically similar to P. boehmeriifolium and P. boehmeriifolium var. glabricaule . Following a detailed comparison with specimens and the academic literature ( De Candolle 1869, Gilbert & Xia 1999), we have determined that P. hongheense can be unequivocally distinguished by several key characteristics, as outlined in the diagnosis above and summarized in Table 1 and Fig. 4 .

Additional specimens examined: — CHINA. Yunnan: Pingbian County of Jinping Prefecture, Shibanxiang , 3 October 1954, G.– M. Feng 04736 ( PE!) ; Pingbian County of Jinping Prefecture, Xinnongxiang , 13 July 1953, P.- Y. Mao 02455 ( KUN!) ; Pingbian County of Jinping Prefecture, Pujijing , 29 March 1958, G.- M. Feng 21778 ( KUN!) .

Figures

FIGURE 1. Piper hongheense W.J. Zhao, C.Y. Hao & N.H. Xia, sp. nov. A habit; B adaxial surface of leaf; C abaxial surface of leaf; D adaxial surface of leaf base and petiole; E abaxial surface of leaf base and petiole; F male spike; G female spike; H mature infructescence; I close-up of portion of the male spike; J close-up of portion of the female spike (some bracts were removed); K close-up of portion of the mature infructescence. Photographs by R. Fan & C.Y. Hao based on the holotype.

FIGURE 2. Line drawing of Piper hongheense W.J. Zhao, C.Y. Hao & N.H. Xia. A branch with female infructescence; B adaxial surface of monopodial leaf on the left, and abaxial surface of sympodial leaf on the right; C detail of the leaf base and the prophyll; D magnified view of male inflorescence; E magnified view of the longitudinal section of male inflorescence; F stamen; G magnified view of female inflorescence; H magnified view of infructescence. Illustration by F. Su based on the holotype.

FIGURE 4. Morphological characteristics of Piper boehmeriifolium and Piper boehmeriifolium var. glabricaule. A Habit of P. boehmeriifolium; B Immature infructescence of P. boehmeriifolium; C Mature infructescence of P. boehmeriifolium; D Habit of P. boehmeriifolium var. glabricaule; E Immature infructescence of P. boehmeriifolium var. glabricaule; F Mature infructescence of P. boehmeriifolium var. glabricaule. Photographs by R. Fan & C.Y. Hao.