Paris lihengiana G.W.Hu & Q.F.Wang, 2019

Xu, Zhun, Wei, Neng, Tan, Ying, Peng, Shuai, Ngumbau, Veronicah Mutele, Hu, Guang- Wan & Wang, Qing-Feng, 2019, Paris lihengiana (Melanthiaceae: Parideae), a new species from Yunnan, China, Phytotaxa 392 (1), pp. 45-53 : 47-51

Paris lihengiana G.W.Hu & Q.F.Wang , sp. nov. ( Figs. 1 , 2 ).

Type:— CHINA. Yunnan Province: Zhaotong City , Weixin County, Daxueshan Forest , 27°53 ′ N, 104° 46 ′ E, elev. 1440 m, 24 April, 2011, Hu, Wang, Zhao HGW-00655 (holotype: HIB; isotype: HIB) .

Paris lihengiana is distinguished from all other Paris species by its pubescent stem, abaxial veins and pedicel and other characters ( Table 2).

Perennial herbs, erect. Rhizome 5.0–8.0 cm long, 0.8–1.0 cm in diam., cylindric, brown externally, white internally, with numerous nodes. Stem 16–40 cm long, green or brownish, covered with silver-grey pubescence. Leaves 5–6 in a whorl at stem apex, 10.0–15.5 × 1.6–2.5 cm, linear-oblong to narrowly elliptic-lanceolate, dark green; apex acuminate, base cuneate or subrotund; petiole ca. 0.5 cm long; adaxial surface glabrous, abaxial surface covered with scattered hairs on veins; leaf margin entire, slightly sinuous, ciliolate; trinerved, veins sunken adaxially and protrudent abaxially. Flower solitary, pedicel 13–16 cm long, green or brownish, with silver-grey hairs. Flower tetramerous or pentamerous; sepals 4 or 5, 2.8–4.0 × 0.8–1.1 cm, lanceolate to narrowly ovate, light green, apex acuminate, base gradually narrowed into a claw, margin ciliolate. Petals 4 or 5, 6.5–7.0 cm, length ca. twice that of sepals, less than 1 mm broad, filiform, green, stamens 12, 16 or 20 in 3 or 4 whorls; filament ca. 5 mm long, green; anthers ca. 8 mm long, basifixed, with convex connective apically, yellow; free portion of connective ca. 0.8 mm long, apex acute. Ovary ca. 8 mm in diam., 3–5-locules distally, uniloculate basally, ribbed, glabrous, bluish violet, incomplete axile placentation, 3–5; stylar base glabrous, sometimes angular; style reddish violet, stigmas 4–5, 4–5 mm long, revolute. Fruits unknown.

Phenology:— Flowering April.

Distribution and habitat:— Known from one location in Daxueshan Forest, Weixin County, Yunnan Province, in subtropical evergreen forest at 1440 m.

Etymology:— Named in honor of Prof. Heng Li, who has made significant contributions to our knowledge of the genus Paris .

Conservation Status:— Because of over-harvesting and lacking of experience in cultivation, most members of Paris are endangered, with numbers of populations sharply declining in the last decade. Increasing demand for medicinal herbs aggravates risk of their extinction. In this case, no additional populations of the new species have been found, although several surveys were done in the original and adjacent areas. According to current information and IUCN Red List criteria (2010), the status of Paris lihengiana would be tentatively classified as critically endangered (CR B2a; B2b(ii)). More extensive fieldwork in surrounding similar habitats is needed to accurately assess its conservation status.

Notes:— Paris lihengiana is morphologically unique although its linear-oblong to narrowly elliptic-lanceolate leaf shape is similar to that of Paris polyphylla var. stenophylla Franchet (1888: 97) . However, the latter has more leaves, (3–)4–7(–8)-merous flower, two whorls of stamens and a loculate ovary. The pubescence on the stem, abaxial leaf surface and pedicel match the basic description of P. mairei Léveillé (1912: 302) . Nonetheless, the latter has a thicker rhizome, obovate to oblanceolate leaves, (4–)5–8(–9)-merous flowers, two whorls of stamens and axile placentation. Paris vaniotii Léveillé (1906: 355) and Paris undulata Li & Soukup (1992: 16) are also similar to P. lihengiana . These three species share features such as thick rhizome, long leaves and angulate ovary. Characters distinguishing P. lihengiana from the other two species are provided ( Table 2).

Molecular phylogenetic analyses:— The topology of BI trees and ML trees are highly congruent, except for the placement of Paris axialis Li (1978: 273) and Paris thibetica var. apetala Handel-Mazzetti (1925: 149) in the ITS analysis. Paris subgen. Daiswa is monophyletic in the plastid trees. Paris lihengiana is placed in subgen. Daiswa and is well supported by the phylogenetic analyses of nrITS ( Fig. 3 ) and plastic DNA data ( Fig. 4 ).

Although P. lihengiana is well resolved as a new species, several phylogenetic problems have been identified in Paris . (1) There is strong discordance between the topology of nrITS and plastid trees. (2) A long branch is generated in plastid DNA analysis. (3) Varieties of Paris polyphylla Smith (in Rees, 1819: 2) are not monophyletic.

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Figures

FIGURE 1. Paris lihengiana. (A) Rhizome and stem. (B) Leaves. (C) Flower. (D) Stamen. (E) Pistil. (F) Ovary (cross section). Drawing by Ling Wang.

FIGURE 2. Paris lihengiana. (A) Habit. (B) Stem, pedicel and abaxial leaf surface (showing pubescence). (C) Leaf adaxial surface. (D) Rhizome. (E–H) Flower. (I) Ovary (cross section). Photographs taken by Guangwan Hu.

FIGURE 3. Bayesian tree based on nuclear ribosomal ITS. Bootstrap value (BS) for maximum likelihood (ML) analyses and posterior probability (PP) for Bayesian analysis are shown (BSML/PPBI). Dashes indicate BSML<50 or PPBI<0.50.

FIGURE 4. Bayesian tree based on plastid DNA data. Bootstrap value (BS) for maximum likelihood (ML) analyses and posterior probability (PP) from Bayesian analysis are shown (BS /PP ). Dashes indicate BS <50 or PP <0.50.