Hemiboea angustifolia F.Wen & Y.G.Wei, 2011

Wen, Fang, Tang, Wen-Xiu & Wei, Yi-Gang, 2011, Hemiboea angustifolia (Gesneriaceae), a new species endemic to a tropical limestone area of Guangxi, China, Phytotaxa 30, pp. 53-59 : 53-58

Hemiboea angustifolia F.Wen & Y.G.Wei , sp. nov. ( Fig. 1 & Fig. 2 A–F )

Haec species H. cavaleriei var. cavaleriei , H. cavaleriei var. paucinervi et H. longgangensi affinis , a quibus foliis anguste lanceolatis vel lanceolatis, floribus majoribus, 4.8–5.4 cm longis, corollae tubis 3.6–4.0 cm longis, orificio 1.4–1.6 cm diametro, ovario (circa 13 mm longo) longiore, disco circa 2.2 mm alto, stigmate capitato, depresso differt.

Type:— CHINA. Guangxi: Daxin County, Encheng Town , growing on the damp stones at the entrance of a medium-sized karst caves where spring runs out from the opening, at evergreen broadleaf forest margins, mostly on soils of limestone crevices somewhat rich in alkaline, altitude 162–170 m, 21 November 2008, F . Wen & W. X. Tang 08112101 (holotype IBK!, isotypes PE!) .

Perennial herb. Stems ascending, 40–80 cm high, 5–7 mm in diameter, rounded, glabrous, simple, with 10–12 nodes or more. Leaves opposite, ca 20, the lower ones commonly caducous; petiole 1–2 cm long, glabrous; leaf blade subcarnose or thinly leathery, thickly herbaceous when dry, narrowly lanceolate to lanceolate, 10.5– 16.5 × 1.5–4.4 cm, apex acute or acuminate, base narrowly cuneate, zygomorphic or slightly oblique, margin entire, glabrous on both sides, lateral veins 5–7 on each side of midrib. Cymes subterminal or terminal, 3- or more-flowered, peduncle 1.0– 1.5 cm long, glabrous; involucre nearly spheroidal or cordate, 1.8–2.3 cm in diameter, whitish green or pale yellowish green, glabrous. Pedicel ca 2.2–3.5 mm long, glabrous. Calyx white or pale green, 5-parted from the base, lobes equal, lanceolate to narrowly triangular, 7.8–8.8 × 0.30–0.35 mm, glabrous. Corolla outside greyish-white or waxy-white, adaxial light purple, inside brownish yellow, 4.8–5.4 cm long, adaxial outside glandular-puberulent, abaxial outside extremely short pubescent to nearly glabrous, inside glabrous; tube 3.6–4.0 cm long, 1.4–1.6 cm in diameter at the orifice, ca 4.8–5.2 mm in diameter at the base, inside with a ring of hairs adnate to 8.0– 8.5 mm above the corolla base; limb distinctly 2-lipped, adaxial lip 2-lobed, lobes oblate, 5.2–6.5 × 8.8–9.3 mm; abaxial lip 3-lobed towards the middle, lateral two lobes rotund, 5.1–5.7 × 5.7–6.3 mm, central lobe oblate or oblate-oval, ca 5.7 × 9.2 mm. Stamens 2, adnate to ca 18.5–19.2 mm above the corolla base; filaments linear, geniculate from the middle, linear, glabrous; anthers slightly elliptic, glabrous, 3.2–3.5 × 2.8–3.0 mm. Staminodes 2, glabrous, adnate to 17.0– 18.1 mm above the corolla base, 5.7–6.0 mm long with adherent capitate apex. Disc ring-like, ca 2.2 mm high, margin repand, glabrous. Pistil 2.5–2.7 cm long; ovary linear, ca 13 mm long, 2.5–2.7 mm in diameter, glabrous; style ca 12– 14 mm long; stigma capitate, middle slightly depressed, ca 1.6 mm in diameter. Capsule linear, ca 3.0– 3.5 cm long, 3.5–4.0 mm in diameter, glabrous, slightly curved. Flowering in November, fruiting in December.

Distribution: — CHINA (Endemic to Daxin County, SW Guangxi Autonomous Region) (see Map. 1).

Habitat & Ecology: — Hemiboea angustifolia has been only found in Encheng Town , Daxin County, Guangxi, China. The climatic type of type locality belongs tropical monsoon climate, the rainfall averages 1326 mm /year, and mean annual temperature was 21.3 °. The vegetation type of this region is special evergreen tropical seasonal rain forest on limestone hills .

Etymology: —The specific epithet refers to the narrow and linear leaves of this new taxon. The morphology of the blade is obviously different from other species in this genus.

Conservation status: —According to the detailed information from our careful field investigation surrounding the type area for five times in two years, the population size of this new species is fewer than 100 individuals, all at one site. They grow on the bottom of limestone cliff in a karst gorge. According to IUCN red list categories ( IUCN 2001, Pullin 2004), we therefore assess Hemiboea angustifolia as Critically Endangered, CR B2ab (i, iii, v) + C2a (ii).

Vernacular name: — CHINA: pizhenye banshuojutai.

Additional specimens examined (paratype): — CHINA. Guangxi: Daxin County, Encheng Town , same locality as type, 21 November 2010, F . Wen & W. X. Tang 10112112 ( IBK!) .

Hemiboea angustifolia is a member of H. sect. Subcapitatae and is similar to H. cavaleriei var. cavaleriei , H. cavaleriei var. paucinervis and H. longgangensis , but differs by narrowly lanceolate to lanceolate, larger greyish-white or waxy-white flowers (4.8–5.4 cm long; tube 3.6–4.0 cm long, 1.4–1.6 cm in diameter at the orifice, 4.8–5.2 mm in diameter at the base), longer pistil and ovary, higher disc and capitate stigma slightly depressed in the middle. The morphology of these taxa, one as a variety, is summarized in Table 1 .

MAP 1. Distribution of Hemiboea angustifolia and related taxa. A) Known distribution of H. angustifolia ; B) Oval area, distribution of H. cavaleriei var. paucinervis ; C) Known distribution of H. longgangensis ; D) Oval dotted line area, distribution of H. cavaleriei var. cavaleriei

Figures

FIGURE 1. Hemiboea angustifolia. A) habit; B) corolla opened with stamens and staminodes; C) stamens; D) pistil with opened calyx; E) stigma; F) transverse section of ovary. Drawn from F.Wen & W.X.Tang 08112101.

FIGURE 2. A–F) Hemiboea angustifolia. A) Habit; B) Involucre; C) Flowers; D) Buds; E) Top view of cyme; F) Opened flower. G–H) Hemiboea longgangensis. G) Habit; H) Flower. I–J) Hemiboea cavaleriei var. paucinervis. I) Habit; J) Involucre and flowers.