Piper jianfenglingense C.Y. Hao & Y.H. Tan, 2017

Hao, Chao-Yun, Qin, Xiao-Wei, Tan, Le-He, Hu, Li-Song, Wu, Gang, Luo, Shui-Xing, Deng, Hai- Yan & Tan, Yun-Hong, 2017, Piper jianfenglingense, a new species of Piperaceae from Hainan Island, China, Phytotaxa 331 (1), pp. 109-116 : 111-112

Piper jianfenglingense C.Y. Hao & Y.H. Tan , sp. nov. ( Figs. 2–3 )

Type: — CHINA. Hainan: Ledong County, Jianfengling National Natural Reserve , tropical lower montane moist forests, ca. 720 m, 18°44’39.38”N, 108°50’49.32”E, 16 July 2015, Chao-Yun Hao 2015066 (holotype HITBC!; isotype HITBC!) .

Diagnosis:— The new species is morphologically similar to Piper mutabile C. DC. (1910: 92) , but it is distinguished by the sparsely pubescent petioles, vaginate at base only; stamens 2, with considerably longer filaments that are caducous when anthers mature; stigmas ovoid, apex acute; rachises glabrous; floral bracts adnate to rachis, margin partially hidden; berries and seeds ellipsoid.

Description:— Woody climbers, more than 6 m high, dioecious. Stems pale green, brown when dry, slender, 0.5–1.2 cm in diameter, finely ridged when dry, glabrous, swollen nodes, with climbing adventitious roots. Leaves chartaceous; glandular; petioles 0.5–1.0 cm long, sparsely pubescent, vaginate at base; adaxial surface green, glabrous; abaxial surface pale green, glabrous; Leaf blade on sterile branches ovate, 3.5–5 × 2.0–3.0 cm, base rounded, symmetric, apex attenuate; veins 5, all basal. Leaf blade on fertile branches elliptic, ovate or ovate-lanceolate, 5.0–9.5× 1.5–3.5 cm, base rounded, symmetric or slightly oblique, apex attenuate; veins 5(–7), apical pair arising 1–3 cm above base. adaxial surface dark green, glabrous; abaxial surface pale green or yellow, glabrous. Inflorescence a pedunculate spike, leafopposed, solitary, pendulous, cylindrical, pale green; the fertile rachis glabrous, with densely compacted flowers; floral bracts orbicular or suborbicular, ca. 2 mm in diameter, adnate to rachis, margin partially hidden. Male inflorescences 3–5 × 0.2–0.4 cm long, pale green; peduncles 1–2 cm long, puberulous. Male flowers with 2 stamens; filaments thick, ca. 0.5–1.2 mm long; anthers subglobose, 0.2–0.4 mm long, 2-locular with lateral dehiscence, exserted at anthesis; filaments caducous when anthers mature. Female inflorescences 2.0–3.0 × 0.3–0.5 cm long, pale green; peduncles 1.0– 1.6 cm long, becoming 1.5–2.5 cm long in fruit, puberulous. Female flowers with ovary ellipsoid to ovoid; style over 2 mm long, persistent and stiff-pointed; stigma ovoid, apex acute, 3- or 4- lobed, hairy. Infructescences 3–5 × 0.8–1.2 cm long, glabrous, pendulous, cylindrical, with an echinate appearance from the persistent styles. Fruit a single-seed berry, connate with rachis, glabrous, ellipsoid, 3.5–5.0 × 3.0–4.0 mm, dark-green. Seed pale brown, ellipsoid, 2.5–4.0 × 2.0–3.0 mm, smooth.

Phenology:— Flowering from May to August; fruiting from July to October.

Etymology:— The epithet refers to its distribution, Jianfengling National Natural Reserve in Hainan Island.

Distribution and habitat:— Piper jianfenglingense is currently known only from Jianfengling National Nature Reserve in Ledong County of Hainan Island ( Fig. 4 ). It climbs on trees or rocks, close to streams in wet tropical montane forest, at elevations of 500– 800 m.

Conservation status:— Piper jianfenglingense is classified as Critically Endangered (CR B2a, IUCN 2012). The total area of occupancy is less than 10 km ² and only two populations are known, despite extensive fieldwork in the area by the first author. The suitable habitats for P. jianfenglingense on the mountain slopes of Jianfengling are endangered due to the increasing deforestation of those regions.

Additional specimens examined (Paratypes):— CHINA. Hainan: Ledong County, Jianfengling National Nature Reserve, ca. 650 m, 18 October 2016, C.-Y. Hao & X.-W. Qin 2016093 (HITBC!).

Figures

FIGURE 2. Piper jianfenglingense. A, B. Habit; C. Adaxial surface of gonophyll; D. Abaxial surface of gonophyll; E. Male spike; F. Female spike; G. Florets in male spike; H. Florets in female spike; I. Infructescence; J. Berry (side view); K. Seed (top view); Photographed by C.-Y. Hao.

FIGURE 3. Piper jianfenglingense.A. Branch with female inflorescence; B. Branch with infructescence; C. Details of male inflorescence (mature); D. Details of female inflorescence (immature); E. Berry (side view); Illustration based on the holotype C.-Y. Hao 2015066.

FIGURE 4. Distribution of Piper jianfenglingense in Hainan Island, China.