Piper peltatifolium C. Y. Hao, H. S. Wu & Y. H. Tan, 2015

Hao, Chao-Yun, Tan, Yun-Hong, Hu, Li-Song, Tan, Le-He, Chen, Hai-Ping, Qin, Xiao-Wei, Wu, Gang & Wu, Hua-Song, 2015, Piper peltatifolium, a new species of Piperaceae from Hainan, China, Phytotaxa 236 (3), pp. 291-295 : 291-293

Piper peltatifolium C. Y. Hao, H. S. Wu & Y. H. Tan , sp. nov. ( Figs. 1–2 )

Similar to P. hongkongense De Candolle (1868: 347) but can be distinguished by the following characteristics: trophophyll leaf blades peltate; leaves subleathery with non-branched hairs; stamens usually only two; anthers ovoid and shorter than filaments; ovary ellipsoid to ovoid; stigmas 3 or 4, and rarely 5; bracts suborbicular, sessile, and adnate to rachis; and drupes slightly hispidulous.

Type: — CHINA. Hainan: Wanning County, Sifang Mountain , moist place at mountain stream sides and under evergreen broad leaved forests, ca. 305 m, 18°43’0.15”N, 110°4’16.94”E, 8 October 2012, Chao-Yun Hao 2012089 (holotype HITBC!; isotype IBSC!, HITBC!) .

Woody climbers, more than 5 m high, dioecious. Stems dark green, brown when dry, 0.5–1.5 cm in diameter, finely ridged, puberulous, or velutinous when young, glabrescent when mature; swollen nodes, with climbing adventitious roots. Leaves subleathery, glandular; petioles 1.5–2.5 cm in length, pilose, sheath 0.4–1.2 cm, 1/4–1/2 as long as petioles; trophophyll leaf blade ovate to cordate, 4.5–6.5 cm × 3.5–5.5 cm, base cordate to auriculate, symmetric, apex attenuate; adaxial surface dark green, glabrous; abaxial surface pale green, puberulous; veins 5, all basal; gonophyll leaf blade peltate, glandular, elliptic, ovate or ovate-lanceolate, 7.5–9 cm × 2.5–5.5 cm, base cordate or rounded, symmetric or slightly oblique, apex attenuate to acuminate; adaxial surface dark green, glabrescent; abaxial surface pale green or yellow, puberulous or pilose, especially on the veins; veins 5, all basal. Inflorescence a pedunculate spike, leaf-opposed, solitary, pendulous, cylindrical, green; the fertile rachis hairy, with densely compacted flowers; floral bracts orbicular or suborbicular, approx. 1.5 mm in diameter, undulate throughout the margin. Male inflorescence 5–7 cm × 0.4–0.5 cm, white to pale green; peduncles 1–2 cm in length, pilose. Stamens usually only two, or rarely three; filaments approx. 1 mm long; anthers ovoid, 0.6–0.8 mm long, 2-locules and lateral dehiscence, ±exserted at anthesis. Female inflorescence 3.5–6.0 cm × 0.4–0.6 cm, white to pale green; peduncles 1.5–2.5 cm long, pilose. Female flowers with ovary ellipsoid to ovoid; style over 2 mm long, persistent and stiff-pointed; stigma star-shaped, 3- or 4-lobed, or rarely 5-lobed, hairy. Infructescence 4–9 cm × 1.0– 1.5 cm, glabrous, pendulous, cylindrical, with an echinate appearance from the persistent styles, peduncles 2.5–4.0 cm long, pilose. Fruit a drupe, connate on rachis and hispidulous, with persistent floral bracts and spine-like styles, globose, 4.0– 6.5 mm in diameter, dark green. Seed pale brown, globose, 2.5–3.5 mm in diameter, smooth.

Phenology:— Flowering from March to May; fruiting from June to September.

Distribution and habitat:— Piper peltatifolium can currently be found only in southern Wanning, Hainan Province, China ( Fig. 3). It climbs on trees or rocks, close to streams under wet tropical montane forest, at elevation of 200– 600 m.

Etymology:— The epithet refers to the peltate attached leaf blade, which is unique in Chinese Piper species.

Relationships:— The species that is morphologically most similar to this new plant is P. hongkongense , which can also be found in Hainan, Guangdong, and Guangxi ( Cheng et al. 1999). After comparison with the specimens and the literature ( De Candolle 1868, Cheng et al. 1999), we found that P. peltatifolium can be clearly differentiated from P. hongkongense by several characteristics, as described in the diagnosis above and summarized in Table 1.

Additional specimens examined (Paratypes):— CHINA. Hainan: Wanning County, Fenghuang Mountain , ca. 430 m, 22 November 2013, C.- Y. Hao & H.- S. Wu 2013154 ( HITBC!) ; Wanning County, Longnanwang , 23 April 1995, F.- W. Xing 6403 ( IBSC!) .

Figures

FIGURE 1. Piper peltatifolium. 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. Drupe (side view); K. Seed (top view); Photographed by C.-Y. Hao.

FIGURE 2. Piper peltatifolium. A. Branch with male inflorescence. B. Branch with infructescence. C. Detail hairs of petiole. D. Adaxial surface of gonophyll; E. Abaxial surface of gonophyll; F–G. Detail of hairs on the leaf blade; H. Floral bracts; I. Male inflorescence; J. Ovary; K. Infructescence; L. Seed; Illustration based on the holotype C.-Y. Hao 2012089.