Petrocodon lancifolius Fang Wen & Y.G.Wei, 2012

Wen, Fang, Liang, Gui-You & Wei, Yi-Gang, 2012, Petrocodon lancifolius (Gesneriaceae), a new species endemic to a central subtropical zone of Guizhou Province, China, Phytotaxa 49 (1), pp. 45-49 : 45-48

Petrocodon lancifolius Fang Wen & Y.G.Wei , sp. nov. ( Figure 1 )

The new species differs from its relative, P. scopulorum (Chun) Y.Z.Wang , by its narrower leaves, leaf blades symmetrical or rarely asymmetrical lanceolate, peduncles, pedicels, the outside of bracts and corolla purplish brown strigulose, corolla campanulate, 4.1–4.5 mm long, limb 4- or 5-lobed, lobes obliquely deltoid or deltoid, stamens 4 or 5, ovary glabrous, pistil 5.4–6.2 mm long, style 3.8–4.2 mm long and sparsely fleshy strigose.

Type: — CHINA. Guizhou province: Huishui County, Duanshan Town , growing on the damp limestone stones at the bottom of hill near to a large sized cave, where stream runs out from the opening, 25°49'N, 106°43'E, elevation 1108–1110 m, 12 July 2009 (fl.), Fang Wen FW-Ges2009071201 (holotype IBK!; isotype BJFC!) .

Perennial herb, acaulescent. Rhizomes terete or subterete, ascending, 2–6 cm long, 1–4 mm in diameter, rooting at the nodes Leaves 11–20 or more, basal; leaf blade coriaceous, usually symmetrical, rarely asymmetrical, lanceolate, 2.5–7.0 × 0.8–1.1 cm, base narrowly cuneate, apex acuminate, acute or obtuse, margin crenate generally up to the middle, more rarely completely crenate or entire to a various degree, glabrous on both surfaces, lateral nerves 3–5 pairs, obviously depressed, midvein raised; petiole 0.9–4.2 cm long, glabrous. Cymes 4–6, 1-branched or not, 4–8-flowered; peduncle 1.5–3.2 cm long, green, purplish brown strigulose; bracts green, linear, 6–9 × 0.8– 0.1 mm, apex obtuse or rounded, margin entire, outside densely scattered purplish brown strigulose, inside glabrous. Flowering pedicel 0.5–0.8 cm long, hairs same as peduncles. Calyx 5-parted to the base, 1.8–1.9 mm long, lobes narrowly lanceolate or lanceolate-linear, outside sparsely purplish brown strigulose. Corolla campanulate, orifice slightly constricted, tube slightly swollen, white, lobes margin slightly green, 4.1–4.5 mm long, 2–2.1 mm in diameter at the middle, 1.6–1.9 mm at the mouth, outside sparsely purplish brown strigulose, inside glabrous; limb 4- or 5-lobed, both sometimes appearing in the same cyme, usually zygomorphic, the adaxial lobes obliquely deltoid, 1.16–1.33 mm long, 1.0– 1.17 mm at the base, apex acute, abaxial lip 2- or 3-lobed to near one third of the lobes, lateral two lobes of 5-lobed flowers or two lobes of 4-lobed flowers obliquely deltoid, 1.2–1.4 mm long, 1.1–1.2 mm at the base, apex acute, the median lobe of 5-lobed flower deltoid, 1.65–1.75 mm long, 1.65–1.75 mm at the base, mauve spot inside. Stamens 4 in 4-lobed flowers, 5 in 5- lobeds flowers, 1.8–2.1 mm long, adnate to the corolla tube base; filaments 1.3–1.5 mm long, straight, anthers cordate, 0.5–0.6 mm long, ca. 0.6 mm at the middle, free, apex acute. Disc ring-like, 0.1–0.2 mm high, entire. Pistil 5.4–6.2 mm long, ca. 0.75–0.8 mm in diameter; style white, 3.8–4.2 mm long, sparsely white fleshy strigose, ovary oblong-cordate, green, glabrous, 1.6–2.0 mm long, stigma 1, capitate, slightly parted to the middle. Capsule unknown.

Distribution and ecology: — Petrocodon lancifolius has been only found in the type locality (see Map 1) and grows on the moist and shaded rock faces at the bottom of a hill near to a large sized cave, where a stream emerges from the opening, elevation 1108–1110 m. The type locality experiences subtropical monsoon climate, the average annual rainfall was 1200 mm, and mean annual temperature was 15.7 °C. The vegetation type is central subtropical evergreen broad-leaved forest on limestone hills.

MAP 1. Distribution of Petrocodon lancifolius () and P. scopulorum (♢) in Guizhou Province, China. (∆): main cities in Guizhou Province.

Etymology:—The specific epithet refers to the narrow and lanceolate leaves of this new taxon. The morphology of the leaf blade is obviously different to P. scopulorum .

Conservation status: —According to the detailed information from our careful field investigation in this area, the population size of this new species is fewer than 500 individuals, all at one site. They grow on the bottom of a limestone cliff in a karst gorge. According to IUCN red list categories ( IUCN 2001, Pullin 2004), we therefore assess Petrocodon lancifolius as Critically Endangered, CR C2a(ii).

Additional specimen examined (paratype): — CHINA. Guizhou Province: Huishui County, Duanshan Town , same locality as type, 07 July 2010, Fang Wen FW-Ges2010070702 ( IBK!) .

Specimens of P. scopulorum examined: — CHINA. Guizhou Province: Xiuwen County, Maochong , in limestone scopulus, 1200 m, 22 July 1991, Shun-Zhi He 91050 ( PE!) , 91051 (PE!), 91052 (HGCM!).

Discussion: — Petrocodon lancifolius is similar to P. scopulorum based on, e.g., the stamen shape, but it can be distinguished by its narrower, usually symmetrical, rarely asymmetrical, lanceolate leaf blade (vs. asymmetrical, elliptic to ovate, rarely obovate), peduncle, pedicels, the outside of bracts and corolla purplish brown strigulose (vs. brown puberulent), corolla campanulate (vs. urceolate, often with long neck), limb 4- or 5-lobed (vs. only 5-lobed), stamens 4 or 5, 1.8–2.1 mm long (vs. only 5, 2.5–3.5 mm long); ovary glabrous (vs. sparsely puberulent), shorter pistil, 5.4–6.2 mm long (vs. 5.5–12 mm long), style sparsely white short fleshy strigose (vs. puberulent). A detailed comparison of the two species is given in Table 1.

Figures

FIGURE 1. Petrocodon lancifolius. A. Habitat, B. Cyme, C. Corolla, D. Opened corolla, showing five corolla segments and five stamens, E. Opened corolla, showing four corolla segments and four stamens, F. Pistil, also showing opened five calyx segments, G. Stigma. Drawn by Y.X. Zhu from Fang Wen FW-Ges2009071201 (IBK).