Piper magen B. Q. Cheng ex C. L. Long & Jun Yang, 2017

Yang, Jun, Wang, Yue-Hu, Luo, Ji-Feng & Long, Chun-Lin, 2017, Piper magen (Piperaceae), a new species from Yunnan, China, Phytotaxa 316 (2), pp. 189-194 : 189-193

Piper magen B. Q. Cheng ex C. L. Long & Jun Yang , sp. nov. ( Fig. 1 and Fig. 2 )

Similar to P. nudibaccatum Y.Q. Tseng (1979: 37) , but distinguished by the following features: woody climbers, the longitudinal ridges of the stem with obtuse, corky wings; leaves at juvenile stage cordate, heterochromous, with veins zone greyish white on the adaxial surface; male spikes with sterile apical region; stamens 3; filaments very short or inconspicuous, flat, ca. 0.1–0.2 mm long; bracts with dense brownish red dots visible on the adaxial surface and with dense cilium on abaxial surfaces (with stereoscope); stigmas 3 or 4, linear, reflexed, sparsely velutinous.

Type:— CHINA. Yunnan: Mengyuan Village, Guanglei Township , Mengla County, climbing on rocks in tropical montane rainforest, 21°45 ′ N, 101°22 ′ E, elev. 1511 m, 5 March 2016, J. Yang YJ-190 (flowering: female)(holotype KUN!; isotype KUN!) .

Woody climbers, more than 3 m high, dioecious. Young stems herbaceous, puberulous, brown when dry, internodes striated, rooting at nodes, tuberculate; older stems woody, glabrous, with numerous longitudinal ridges, each with obtuse, corky wings. Leaves dimorph, cordate, heterochromous at juvenile stage, 3–7 × 3–5.5 cm, with dots; veins 5–7, palmate, major veins zone greyish white on adaxial surface, veins green, puberulous on abaxial surface; petioles 0.5–2 cm long, puberulous; mature leaves green, elliptic to ovate at adult stage, 9–18 × 4–10 cm, membranous to papery, glabrous, base asymmetrical, with one side rounded, 2–3 mm longer that the other side, cuneate, apex acuminate to long-acuminate; major veins 7–9, pinnate, apical pair veins separating from each side of midvein ca. 1–4 cm from base; reticulate veins abaxially prominent; petioles 1–2 cm long, glabrous, sheaths nearly half of petiole length or longer. Spikes leaf-opposed; peduncle ca. 1–2 cm long, glabrous, as long as or slightly longer than petiole; bracts suborbicular, ca. 1 mm in diam., nearly sessile, margin irregular, with dense, brownish red dots visible on adaxial surface and with dense cilium on abaxial surfaces (with stereoscope). Male spikes 3.5–8 cm × ca. 3 mm, with sterile apical region ca. 1–3 mm long; stamens 3/flower; filaments very short or inconspicuous, flat ca. 0.1–0.2 mm long (with stereoscope); anthers reniform. Female spikes 2–5 cm × ca. 5 mm; stigmas 3 or 4/flower, linear, reflexed, sparsely velutinous. Drupes globose, partly immersed in rachis, glabrous.

Distribution: —Only two populations are known of this species, which are apparently restricted to the area of Mengla County, southern Yunnan, China ( Fig. 3 ).

Ecology and Habitat: —This species climbs on rocks, at elevations of ca. 1500 m, in dry shade in tropical, montane rainforests.

Phenology: —Flowering from April to June; fruiting from July toSeptember.

Etymology: —The epithet refers to the old stem with numbing or spicy taste.

IUCN Red List Category: — Piper magen is known only from Mengyuan Village, Guanglei Township, Mengla County, southern Yunnan Province, China. It is distributed in two localities separated by approximately 30 km. The habitats are close to villages and the local people like eating this plant (stem and leaves) as a favorite spice. Less than 20 individuals were found in each population and almost all of them are juvenile. This new species was evaluated as Critically Endangered [CR B1b (iii)] because of its limited distribution and threatened habitat, according to the IUCN Red List Categories and Criteria ( IUCN 2012).

Taxonomic relationships: —The species that is morphologically similar to this new species is P. nudibaccatum , which can also be found in Yunnan Province ( Tseng 1979, Cheng et al. 1999, Gilbert & Xia 1999). After comparing with specimens of P. nudibaccatum and descriptions in the literature ( Tseng 1979, Cheng et al. 1999, Gilbert & Xia 1999), we determined that P. magen can be clearly differentiated on the basis of several characteristics, as described in the diagnosis above and summarized in Table 1.

Additional specimen examined: — CHINA. Yunnan: Mengyuan Village, Guanglei Township , Mengla County, climbing on rocks near the village, 21°42 ′ N, 101°22 ′ E, elev. 920 m, 21 December 2014, J. Yang YJ-042 (male) ( KUN!) ; 28 July 2012, J. Yang YJ-008 (male) ( KUN!). Both specimens were collected at the same place, about 30 km from the type locality .

Figures

FIGURE 1. Piper magen. A. Habit; B. Juvenile; C. Adaxial surface of adult leaf; D. Abaxial surface of adult leaf; E. Male spike; F. Female spike; G. Infructescence; H. Woody stem; I. Young stem; J. Floral bracts and stamens; Photographed by J. Yang.

FIGURE 2. Piper magen. A. Branch with male inflorescence; B. Branch with infructescence; C. Juvenile; D. Woody stem; E–F.A portion of the male inflorescence; G. Stamen; H. Floral bract frontal view; I. Floral bract lateral view; J. A portion of the infructescence; Drawn by L. Wang. Illustration based on the holotype J. Yang YJ-190 (female), and the paratypes J. Yang YJ-008 (male) and J. Yang YJ-042 (male).

FIGURE 3. Distribution of Piper magen in Mengla County, China.