Petrocosmea nanchuanensis Z.Y. Liu, Z.Y. Li & Z.J. Qiu, 2020

Qiu, Zhi-Jing, Zhang, Jun, Baskaran, Xavier-Ravi, Hu, Jin, Li, Zhen-Yu & Liu, Zheng-Yu, 2020, Petrocosmea nanchuanensis (Gesneriaceae), a new species from Chongqing, China, PhytoKeys 157, pp. 137-144 : 137

Petrocosmea nanchuanensis Z.Y. Liu, Z.Y. Li & Z.J. Qiu sp. nov. Figs 1 , 2

Diagnosis.

Petrocosmea nanchuanensis is morphologically similar to P. barbata Craib, but is distinguished from the latter by smaller leaves, a repand leaf margin, densely appressed longer pubescences on both surfaces of its leaves, larger flower with the length of its lower lips three times longer than that of the upper lips, oblong lower lip lobes, shorter pistil, ovate anthers and styles that are shortly pubescent or approximately glabrous above the middle.

Type.

China. Chongqing Municipality: Nanchuan, Banhegou, Mt. Jinfo, 20 Sep 2002. Z. Y. Li 2002016 (holotype, PE).

Description.

Perennial herb, rosette-forming, with a short rhizome and crowded fibrous roots. Leaves 8 to 30, all basal, crowded, the inner leaves with short or absent petioles, the outer leaves with longer petioles; leaves orbicular-ovate, broad-ovate, cordate or almost circular, 0.5-2 × 0.7-2 cm, herbaceous, apex round, base cordate, margin undulate teeth, both surfaces with densely villous, lateral veins 3 on each side, not distinct; petioles 0.5-6 cm, densely pilose. Cymes 5 to 15, 1-3 flowers per cyme; peduncle 3-10 cm, densely pilose; bracts 2 at upper- or middle-peduncle, lanceolate, 0.5-1.2 cm, pubescent, pedicel 1-5 cm, densely hairy; sepals 5-divided to the base, narrow-lanceolate, ca. 4-5 mm, pubescent externally. Corolla light purple or white, outside and inside abaxial lip puberulent, inside adaxial lip and tube near mouth densely pubescent, 2 yellow spots inside abaxial lip base; tube ca. 3 mm, adaxial lip ca. 3-3.5 mm, bi-lobed near to base, lobes ovate, abaxial lip ca. 8-9 mm, deeply tri-lobed, lobes oblong; stamens 2, ca. 2.2 mm; filaments adnate to ca. 1 mm above the base of corolla tube, ca. 1.2 mm long, glabrous; anthers ovate, ca. 1 mm long, glabrous; staminodes 3, adnate to ca. 0.2-0.4 mm above the base of the corolla tube, ca. 0.3-0.8 mm long, glabrous; pistil ca. 4.5 mm; ovary densely villous, ovoid, oblique abaxially, ca. 1.5 mm long; style unfolded pilose and glandular hairs under the middle, shortly pubescent or approximately glabrous above the middle, ca. 3 mm long.

Habitat and distribution.

Petrocosmea nanchuanensis grows on moist shady limestone cliffs or along forest edges at an altitude of 600-650 m on the Mt. Jinfo, Banhe valley, Nanchuan District, Chongqing Municipality, which is adjacent to Guizhou Province in south-western China.

International Union for Conservation of Nature (IUCN) Red List Category.

The new species is determined to be Critically Endangered (CR A2c) according to the IUCN Red List of Threatened Species Categories and Criteria ( IUCN 2001). About 850 individuals were found in two separate and restricted populations: 300 individuals were found growing in one location with ca. 4 × 2 m2 and 550 individuals were found at the other location with ca. 8 × 3 m2. Petrocosmea nanchuanensis is only known from the type locality, i.e. Nanchuan District and their habitat has been threatened and damaged by deforestation and over-exploitation due to native tourism despite its protection in the Mt. Jinfo National Nature Reserve.

Phenology.

The new species was collected with flowers during September-November; fruits were not seen.

Additional specimens studied (paratypes).

China. Chongqing: Mt. Jinfo, Nanchuan, 3 Sep 2007, R. H. Liang 2007010 (PE), Z. J. Qiu 2011020, QZJ-20131082 (SZG), S.Z. Zhang 20121077 (SZG), Z. Y. Liu 500119-1582ly, 500119-1595ly (IMC).

Figures

Figure 1. Drawing of Petrocosmea nanchuanensis Z. Y. Liu, Z. Y. Li & Z. J. Qiu, sp. nov. A habit B stamens C dissected corolla D calyx and pistil.

Figure 2. Petrocosmea nanchuanensis Z. Y. Liu, Z. Y. Li & Z. J. Qiu A habitat B flowering plants C flower, front view D flower, side view E flower, front view, showing pistil and anthers F hairs on abaxial leaves G stamens H hairs on the pistil.