Viola shiweii Xiao C. Li & Z. W. Wang, 2022

Li, Xiao-Chen, Wang, Zheng-Wei, Wang, Qi, Ge, Bin-Jie, Chen, Bin, Yu, Ping & Zhong, Xin, 2022, Viola shiweii, a new species of Viola (Violaceae) from karst forest in Guizhou, China, PhytoKeys 196, pp. 63-89 : 63

publication ID	https://dx.doi.org/10.3897/phytokeys.196.83176
persistent identifier	https://treatment.plazi.org/id/2EEA7109-CB24-54DD-9C0A-9C30C75088C3
treatment provided by	PhytoKeys by Pensoft
scientific name	Viola shiweii Xiao C. Li & Z. W. Wang
status	sp. nov.

Treatment

Viola shiweii Xiao C. Li & Z. W. Wang View in CoL sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3 : Figs A1 View Figure A1 , A2 View Figure A2 , A3 View Figure A3 , A4 View Figure A4 , A5 View Figure A5 , A6 View Figure A6 , A7 View Figure A7 , A8 View Figure A8 , A9 View Figure A9 , A10 View Figure A10 , A11 View Figure A11 , A12 View Figure A12

Type.

China. Shanghai Chenshan Botanical Garden, cultivated plants collected from Guizhou, Qiannan Buyi and Miao Autonomous Prefecture (黔南布依族苗族自治区), Libo county (荔波县), Maolan National Nature Reserve (茂兰国家级自然保护区), on the rocks along the karst forest margin, 25°16'39.1039"N, 107°55'2.7598"E, 867 m elevation, 9 Nov 2019, Wang Zheng-wei and Li Xiao-chen, LXC00927 View Materials Holotype: CSH0182173 (CSH!); isotypes: ZJFC!, CSFI!, IBSC GoogleMaps !.

Diagnosis.

The new species is morphologically most similar to V. kwangtungensis Melchior in its glabrous lateral petals and stoloniferous habit, but can be distinguished by its obtuse teeth along the leaf margin, its abaxially pale green leaf blade and its broader and entire sepals with a distinct basal appendage.

Description.

Perennial herb, acaulescent, with stolons. Rhizome short, straight or oblique, densely noded, usually covered by brown remains of stipules. Stipules free, brown, broadly lanceolate, 5-10 mm long, margin long fimbriate-dentate, lobes remotely dentate. Basal leaves glabrous, slightly grooved, with petioles stout, petioles unequal in length; blade thick leathery, ovate or suborbicular, 15-30 × 15-20 mm, base deep cordate, apex usually obtuse, abaxially green, scabrous, abaxially greyish-green, mid-vein distinct above, glabrous on both surfaces, margin glandular-serrate or shallowly glandular-crenate, slightly wavy, teeth obtuse at the apex; stolon leaves scattered, smaller. Pedicel equal to or longer than petiole, two bracts narrowly lanceolate, at the middle or lower part of the pedicel. Sepals 5, ca. 6 mm long and 2 mm wide, lanceolate, glabrous, margin narrowly membranous, apex somewhat acute, base distinctly decurrent, apex obtuse or shallowly dentate. Flower 1.5-2.5 cm in diameter, petals 5, white, posterior and lateral ones obovate, ca. 1.2 cm × 5 mm, narrow at the base, lateral petals purplish near the middle, glabrous, anterior petal shorter, ca. 10 mm (spur included) long, oblong, purple-veined, apex rounded, obtuse, spur saccate, 2-3 mm long and 1.5 mm wide. Style clavate, base geniculate, stigmas flattened on top, narrowly margined on lateral sides and abaxially, shortly beaked ventrally. Capsule ellipsoid, valves carinate, ca. 10 mm long and 2.5 mm wide, glabrous. Seeds black, ca. 2 mm long and 1 mm in diameter.

Distribution and habitat.

The species was observed to grow on dry and partially shaded limestone, around the karst forest edge, at 700-900 m elevation.

Additional specimens examined.

China, Guizhou, Qiannan Autonomous Prefecture, Libo County, Maolan National Nature Reserve , karst forest, 24 Jul 2008, Zhang Dai-Gui 080724077 (JIU!) ; China, Guizhou, Qiannan Buyi and Miao Autonomous Prefecture , Libo County, Maolan National Nature Reserve , 21 Nov 2021, Li Xiao-chen, Wang Zheng-wei & Wei Hong-jin, LXC02320 View Materials (CSH!), LXC02322 View Materials (CSH!), LXC02323 View Materials (CSH!), LXC02324 View Materials (CSH!), LXC02325 View Materials (CSH!) .

Phenology.

Cultivated plants flower in September-March, fruiting in September.

Etymology.

The specific name epithet " shiweii " was proposed in memory of Deng Shi-wei (191?-1936), who dedicated his life to the exploration of the flora of Guizhou. The Chinese name is given as “世纬堇菜”.

Conservation status.

Only two populations of V. shiweii are currently known from Maolan National Nature Reserve, Libo County, in an area of the karst formation across Guizhou and Guangxi (Fig. 4 View Figure 4 ). This species is represented by no more than 200 large and mature individuals. Due to its rarity, the low number of individuals and habitat vulnerability, V. shiweii is considered to be Critically Endangered (CR, B1), according to the IUCN (2019).