Petrocosmea hexiensis S.Z.Zhang & Z.Y.Liu, 2012

Qiu, Zhi-Jing, Wang, Xiao-Ling, Liu, Zheng-Yu, Yang, Jian-Fen & Zhang, Shou-Zhou, 2012, Cytological and phylogenetic study of Petrocosmea hexiensis (Gesneriaceae), a new species from Chongqing, China, Phytotaxa 74 (1), pp. 30-38 : 35-37

Petrocosmea hexiensis S.Z.Zhang & Z.Y.Liu , sp. nov. ( Figure 4–5 )

The new species is similar to Petrocosmea duclouxii , but differs from it mainly by having ovate-rhombic to rhombic leaf blades with cuneate bases and corollas with longer (2–4 mm) tubes.

Type: — CHINA. Chongqing: Nanchuan, Hexi , 1 April 2011. Z. Y . Liu 110128 (holotype SZG!) .

Perennial rosette-forming herbs, with short rhizomes and crowded fibrous roots. Leaves 20 to 60 per plant, all basal, crowded, the inner leaves with short petioles, the outer leaves with longer petioles, petioles 0.5–3.5 cm long, densely pilose; leaf blades ovate-rhombic torhombic, 0.5–1.1(–1.5) × 1.0–2.2(–2.5) cm, herbaceous, bases cuneate, margins repand-crenate, apices acute,; both surfaces densely appressed-pubescent, lateral veins 3 on each side, not distinct;. Cymes 6 to 15, 1 flower per cyme; peduncles 3–8 cm long, densely pilose; calyx 5-lobed nearly to base, lobes narrow-lanceolate, the adaxial three lobes longer, ca. 3.5 mm, the abaxial two lobes shorter, ca. 3 mm, pubescent externally. Corolla light-purple, puberulent outside and within, 2 deep purple spots inside the tube throat; tube 4.5–5.5 mm, adaxial lip ca. 1.5–2.5 mm, 2-lobed nearly to the base, lobes ovate, abaxial lip 4.5–5.5 mm, 3-lobed to the middle, lobes ovate; stamens 2, ca. 3.8 mm; filaments adnate to ca. 1 mm above base of corolla tube, ca. 1.9 mm, sparsely pubescent; anthers ovate, poricidal, ca. 1.9 mm long, glabrous; staminodes 3, adnate to ca. 0.2–0.3 mm above base of corolla tube, 0.3–0.5 mm, glabrous; pistil ca. 7 mm; ovary densely villous, ovoid, oblique adaxially, ca. 1.5 mm; style sparsely pubescent bellow the middle, ca. 5.5 mm, close to the adaxial corolla tube. Capsules straight in relation to pedicel, brown, long ellipsoid, ca. 0.5 mm, both loculicidally and septicidally dehiscent.

Habitat and distribution: — Petrocosmea hexiensis grows on moist shady cliffs on limestone hills, at 800–900 m elevation in Sanjing valley , Hexi town , Nanchuan district of Chongqing, adjacent to Guizhou Province, in Southwestern China .

Phenology: —The new species has been collected in flower in April–May; fruiting May–June.

IUCN Red List category: —The new species is determined as Critically Endangered ( CR A2 c) according to the IUCN Red List criteria ( IUCN 2001). About 300 individuals were found in only one restricted population in the locality of ca. 2× 4 m 2. Petrocosmea hexiensis is only known from the type locality in the Sanjing Valley near Hexi town. The habitat of this new species has been threatened and damaged by overexploitation by native populations, tourism and farming .

Additional specimens studied (paratypes): — CHINA. Chongqing: Nanchuan , Hexi, same locality as type, 1 April, 2011, Z . Y . Liu 110129 ( SZG!), Z . J . Qiu 2011115 ( SZG!), S . Z . Zhang 114401 ( SZG!) .

Figures

FIGURE 4. Drawing of Petrocosmea hexiensis. A. Habit; B, C. Flowers; D. Pistil; E. Dissected corolla; F. Sepal; G. Stamens; H. Fruit; I. Partial enlarged leaf; J. Enlarged hairs on the leaves.

FIGURE 5. Photographs of Petrocosmea hexiensis (A, C, E, G) and its relative P. duclouxii (B, D, F, H). A–B. Fruiting plants in their habitat. C–D. Plant. E–F. Flower front view. G–H. Corolla tube side view.