Piper puerense C.Y. Hao & F. Su, 2022

Su, Fan, Ji, Xun-Zhi, Wu, Bao-Duo, Qin, Xiao-Wei & Hao, Chao-Yun, 2022, Piper puerense, a new species of Piperaceae from Yunnan, China, Phytotaxa 575 (2), pp. 159-165 : 161-162

Piper puerense C.Y. Hao & F. Su , sp. nov. ( Figs. 1–2 )

Type: — CHINA. Province Yunnan: Puer County, Simao District , Taiyanghe National Natural Reserve , tropical montane rain forests, ca. 1585 m, 22°35’56.51”N, 101°06’51.30”E, 4 May 2020, C.-Y. Hao 2020054 (holotype HITBC!; isotypes HITBC!, Herb. of SBRI!) .

Diagnosis:— The new species is morphologically similar to P. curtipedunculum , but can be distinguished by the stems (densely roughly pubescent when young, glabrous when mature vs. glabrous), leaf blades (ovate, 8.5–12 cm × 4.3–6.5 cm vs. ovate or narrowly ovate to elliptic, 9–14 × 4–8 cm), female inflorescence length (12–18 cm vs. 9–14 cm), male inflorescence length (20–30 cm vs. 13–15 cm), bracts diameter (1–2 mm vs. 0.5 mm), infructescence (15–22cm vs. 8–15cm), peduncle (1.5 cm, nearly 2 times larger than the petiole vs. 0.5–1cm, subequal to petiole), and fruit diameter (1.0– 1.5 mm vs. 0.7–1.0 mm).

Woody climbers, more than 5 m high, dioecious. Stems pale green, black brown when dry, 0.6–1.2 mm thick, finely ridged when dry, densely pubescent when young, glabrous when mature, with climbing adventitious roots. Leaves chartaceous, glandular, adaxial surface dark green, abaxial surface pale green. Leaf blade on the monopodial branches ovate to cordate, 5.0–8.0 cm long, 3.5–6.0 cm wide, base cordate to auriculate, symmetric or slightly asymmetric, apex acute; adaxial surface glabrous; abaxial surface pubescent, especially on the veins; veins 7, reticulate veins conspicuous, multiplinerve, apical pair arising 0.5–1.5 cm above base, alternate, reaching leaf apex, others basal; petioles 1.0–2.0 cm long, pubescent, prophyll ca. 1/3 as long as petioles or longer. Leaf blade on the sympodial branches ovate, chartaceous, glandular, 8.5–12 cm × 4.3–6.5 cm; leaf blade base oblique, usually one side broad and rounded, other side narrow and cuneate, bilateral difference 2–4 mm; leaf blade apex attenuate to acuminate, glabrous; veins (7–)9, reticulate veins conspicuous, multiplinerve, apical pair arising 2.5–4.0 cm above base, alternate, reaching leaf apex, others basal, glabrous; petioles 0.5–1.0 cm long, sheathed at base only, glabrous. Inflorescence a pedunculate spike, leaf-opposed, solitary, pendulous, cylindrical; the fertile rachis pubescent, with densely compacted flowers; floral bracts orbicular, ca. 1–2 mm diameter, peltate, glabrous, stalk 0.5–1.5 mm long. Male inflorescences 20–30 cm long, 3–4 mm diameter, green when young, white when mature; peduncles 1.0–2.0 cm long, glabrous. Male flowers with 2 stamens; filaments short; anthers subglobose, 2-locular with lateral dehiscence. Female inflorescences 12.0–18.0 cm long, 3–4 mm diameter, green when young, light yellow when mature; peduncles 1.0–2.0 cm long, glabrous. Female flowers with ovary globose, distinct; style short, persistent and stiff-pointed; stigma ovoid, apex acute, 3-lobed. Infructescences 15–22 cm long, 0.5–0.7 cm diameter, glabrous, pendulous, cylindrical, with an echinate appearance from the persistent styles. Berry obovate, 1–1.5 mm in diameter, partly connate to rachis, glabrous, green. Seed dark brown when mature, ellipsoid, 0.9–1.2 mm long × 0.7–1.0 mm wide, smooth.

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

Etymology:— The epithet refers to its distribution, Puer County in Yunnan province.

Distribution and habitat:— Piper puerense is currently known only from Puer County of Yunnan Province in China ( Fig. 3 ). It occurs in wet subtropical and tropical montane forest at elevations of 1500–2200 m, and often climbs on trees or rocks close to streams.

Conservation status:— Piper puerense is classified as Critically Endangered (CR B2a, IUCN 2012). The total area of occupancy is less than 5 km 2 and only two populations are known, despite extensive fieldwork in the area by the first author. The suitable habitats for P. puerense on the mountain slopes are endangered due to the deforestation of those regions.

Taxonomic affinities:— The species that is morphologically most similar to this new plant is P. curtipedunculum C. De Candolle , which can be found in S. Guizhou, SE to SW Yunnan ( Tseng 1979). After comparison with the specimens and the literature ( De Candolle 1868, Tseng 1979), we found that P. puerense can be clearly differentiated from P. curtipedunculum by several characteristics, as summarized in Table 1 .

Additional specimens examined (Paratypes):— CHINA. Puer of Yunnan Province: Jingdong County, Wuliangshan National Nature Reserve , ca. 1895 m, 24°29’21.44”N, 100°42’46.84”E, 7 October 2020, C.-Y. Hao 2020067 (HITBC!) .

Figures

FIGURE 1. Piper puerense. A. Branch with infructescence; B. Branch with male inflorescence; C. Monopodial branch; D. Detail of leaf petiole on the monopodial branches; E. Leaf on the monopodial branches; F. Detail of leaf blade on the monopodial branches; G. Detail of female inflorescence; H. Detail of male inflorescence; I. Detail of infructescence; J. Seed (Side view). Illustration by Jue Wang based on the holotype.

FIGURE 2. Piper puerense. A. Habit; B. Monopodial branch; C. Infructescence; D. Male spike; E. Adaxial and abaxial surface of leaf blade on the sympodial branches; F. Detail of leaf petiole on the monopodial branches; G. Detail of leaf petiole on the sympodial branches; H. Detail of male spike; I. Detail of female spike; J. Detail of infructescence; K. Longitudinal sections of infructescence; L. Seed (side view); M. Longitudinal sections of seed. Photographed by C.-Y. Hao.

FIGURE 3. Distribution of Piper puerense in Puer County, Yunnan Province, China. Light red dot: collection locality of specimen C.-Y. Hao 2020054, light red dot: collection locality of specimen C.-Y. Hao 2020067.