Dysosmavillosa (Berberidaceae), a new species from Guizhou, Southwestern China

Abstract A new species, Dysosmavillosa Z.W.Wang & H.C.Xi, is described and illustrated based on collections from the Yueliang Mountains in Congjiang County of Guizhou, Southwestern China. It is morphologically similar to D.difformis (Hemsl. & E.H.Wilson) T.H.Wang ex T.S.Ying, but can be easily distinguished from D.difformis by its inflorescences bearing a greater number of flowers (5–13 vs. 2–5), white-villous stems, petioles, and abaxial leaf blade, and stigma dark purple-red. In addition, we also compare this new species to the three species of Podophyllum (i.e., P.glaucescens J.M.H.Shaw, P.hemsleyi J.M.H.Shaw & Stearn, and P.trilobulum J.M.H.Shaw) which are insufficiently known and listed as putative members of Dysosma in Flora of China. Dysosmavillosa can also be easily distinguished from P.glaucescens (7-flowered; to 40 cm tall) and P.hemsleyi (4-flowered; to 40 cm tall) by its inflorescences bearing a greater number of flowers, relatively smaller stature (9–23 cm tall), stems, petioles and abaxial leaf blade densely white-villose. Although the stems and petioles of P.trilobulum also possess fine short hairs, it can be easily distinguished from D.villosa by its trilobulate leaves, inflorescence with fewer flowers (2–5), and the position of inflorescence (inserted at or above midpoint on petiole of upper leaf).


Introduction
Dysosma Woodson, a small genus of Berberidaceae, has long been used in traditional herbal medicine in East Asia due to the presence of podophyllotoxin, which has important biological activities, such as treating external genital warts (Beutner and Von 1990, Wang 1991, Petersen et al. 1995, Ying et al. 2011, Mao et al. 2014. It occurs at the Subtropical Evergreen Broadleaved Forest belt of China, being morphologically close to Sinopodophyllum (Royle) T.S.Ying, Podophyllum L., and Diphylleia Michx. Nonetheless, it is differentiated by comprising perennial herbs with creeping rhizomes, numerous fibrous roots, 3-9-parted or lobed-peltate leaves, umbellate inflorescences, and berries with numerous seeds (Stähelin and Von 1991, Ying et al. 2011, Mao et al. 2014. Recently, a large number of phylogenetic analyses revealed the monophyly of Dysosma and its sister relationship to the Sinopodophyllum and Podophyllum (Loconte and Estes 1989, Nickol 1995, Kim and Jansen 1998, Liu et al. 2002, Wang et al. 2007, Mao et al. 2014 (Ying et al. 2011). In addition, due to inadequate material, FOC also treats three insufficiently known species described under Podophyllum (i.e., P. glaucescens J.M.H. Shaw, P. hemsleyi J.M.H.Shaw & Stearn, and P. trilobulum J.M.H.Shaw), but that probably belong to Dysosma (Ying et al. 2011).
During a field trip to the Yueliang Mountains, Congjiang County, Guizhou Province, Southwestern China, in May 2015, an unknown species with densely white-villous stems, petioles and abaxial leaf blade, and dark purple-red stigma was found. After a detailed examination of the characters of our material and possible closely similar species in Dysosma (including the three species of Podophyllum which are putative members of Dysosma), we concluded that these specimens actually represent an undescribed species. Thus, due to its uniqueness in characters, it is formally described by us, below.
Distribution and habitat. This new species is currently known from Yueliang mountains of Congjiang County, Guizhou Province, Southwestern China. It grows under forests, at an elevation between 800 and 1500 m.
Phenology. This new species has been observed flowering from April to June and fruiting from June to September.
Etymology. The specific epithet is derived from the character (white-villous petioles, stems and abaxial leaf blade) of this species.

Discussion
Dysosma villosa shares certain characteristics with D. difformis in having alternate leaves, leaf blades not deeply divided and/or undivided, inflorescence attached near the base of leaf blade, and oblong-loriform petals. However, it can be promptly recognised by its inflorescences generally having more flowers, and densely white-villose stems, petioles and abaxial leaf blade. Particularly, its densely white-villose stems, petioles and abaxial leaf blade and dark purple-red stigma are significantly different from D. difformis, as well as other species of Dysosma. In addition, it is worth mentioning that there are still three uncertain species described under Podophyllum (P. glaucescens, P. hemsleyi, and P. trilobulum) that probably belong to Dysosma (Shaw 2002, Ying et al. 2011. However, they are also found to be significantly different from D. villosa after we checked their morphological description (Ying et al. 2011) and images of type specimens from JSTOR Global Plants (http://plants.jstor.org). For instance, though the stem and petioles of P. trilobulum were also found with hairs, it was significantly different from D. villosa due to its trilobulate lobed leaves, inflorescence with fewer flowers (2-5) and the position of inflorescence (inserted at or above the midpoint on the petiole of the upper leaf ). Comparisons of the key characters amongst D. villosa, D. difformis and the three insufficiently recognised species are listed in Table 1.