Actinostephanus enpingensis F.Wen, Y.G.Wei & Z.B.Xin, 2022

Wen, Fang, Xin, Zi-Bing, Hong, Xin, Cai, Lei, Chen, Xiao-Yun, Liang, Jun-Jie, Wang, Hui-Feng, Maciejewski, Stephen, Wei, Yi-Gang & Fu, Long-Fei, 2022, Actinostephanus (Gesneriaceae), a new genus and species from Guangdong, South China, PhytoKeys 193, pp. 89-106 : 89

Actinostephanus enpingensis F.Wen, Y.G.Wei & Z.B.Xin sp. nov.

Figs 3 , 4

Type.

China. Guangdong province, Enping city, Naji town, Qixingkeng provincial natural reserve, growing on the cliffs or slopes of montane yellow soil and sandy loam near a stream. 22°11.1808'N, 112°5.841'E, ca. 153 m, Chen Xiaoyun & Liang Junjie 210519-01 (holotype: IBK!, isotypes IBK!) .

Description.

Herbs, perennial, acaulescent, or forming elongated rhizome slightly fleshy after some years, rhizomes cylindrical, surfaces densely brown pubescent, 5-15 mm long, 3-8 mm in diam., fibrous root filiform, 4-6 cm long, up to 10 cm, forming adventitious buds and plantlets in the middle or at the end of fibrous root. Leaves all basal, whorls of three, sometimes opposite, all closely clustered at top forming rosette, or clustered forming rosette at the top of rhizome after years of growth, (8)9-(16)18 or more, subsessile or shortly petiolate, short petiole cylindrical, 6-15 × 3.5-4.8 mm, densely brown villous. Leaf blades chartaceous to thickly herbaceous, thin chartaceous when dried, obovate elliptic, occasionally obovate lanceolate, greenery to green, dark green after a year of growth, 7.5-15.0 × 3.5-6.0 cm, asymmetric, rarely symmetric, attenuate to base and base usually oblique, rarely aequilateral, apex rounded, obtuse to subacute, margin numerous crenulate, adaxial surfaces of young leaf blades sparsely puberulent, subsequently gradually deciduous, adaxial surfaces of mature leaf blades nearly glabrous, but abaxial surfaces of young and mature leaf blades pubescent, covered by long and obvious strigose hairs along the main and lateral veins; venation alternate along main vein, lateral veins 7-9 on each side of the midrib, main and lateral veins on adaxial surface obviously sunken and on abaxial surface distinctly prominent. Inflorescence dichasium, 4-8, axially, 8-14-flowered, rarely 4-5-flowered and occasionally more than 14, 1-2-branched; peduncle sturdier, 2.2-4.5 cm long, 1.0-1.5 mm in diam., brownish-green to brownish-red, densely upward short strigose, the hairs brownish red, occasionally pink to pinkish white. Bracts 2, brownish-green, opposite, linear-lanceolate, ca. 6.0 × 1.0 mm, adaxial surface appressed pubescent, abaxial surface puberulent, apex acute, margin entire; pedicel 4.0-9.0 mm long, ca. 1.0 mm in diam., pale brownish-green to green, pubescent. Calyx actinomorphic, 5-parted to the base, segments pinkishwhite, pale pinkish-purple to pale brownish-red, equal, lanceolate, 3.5-4.0 × 1.2-1.4 mm, apex acute, margin entire, abaxial surface puberulent, adaxial surface glabrous, but persistent in the fruiting period. Corolla pale purple to pale bluish-purple, actinomorphic, bowl-shaped, 4.0-5.0 mm long/high, 65-75 mm in diam., outside puberulent, inside nearly glabrous and sparsely very few glandular-puberulent; tube very short, 1.5-2.0 mm long/high, shallow bowl-shaped; limb quinquelobate, lobes equal, half elliptic, the major axis ca. 3.5 mm long, the minor axis ca. 1.2 mm long, apex cambered, margin revolute. Stamens 4, separated, filaments nearly slender cylinder, glabrous, two longer and two shorter, longer pairs ca. 1.5 mm long, shorter pairs ca. 1.0 mm long, the four adnate to the base of corolla tube, anthers dorsifixed, free, cordate, yellowish-brown to pale greenish-brown, ca. 1.0 mm height, ca. 1.0 mm across at the bottom of the cordate shape, dehiscing longitudinally, glabrous. Disc wax yellow, ca. 1.0 mm high, glabrous, smooth, margin crenulate. Pistil 4.5-4.8 mm long, ovary pale pink, conical, sparsely inconspicuously puberulent, ca. 0.9 mm long, ca. 1.0 mm across at bottom, style translucent to white, 3.8-4.0 mm long, stigma punctate, yellow. Capsule oblong-ovoid, 4.5-5.0 mm long, 1.2-1.3 mm across, appressed villous, wrapped by persistent calyx lobes and the abaxial surfaces of calyx lobes densely pubescent; capsule hard when mature, style usually persistent, rarely dehiscent, occasionally split into 4-valves. The number of seeds per capsule fewer than 100, only 50-80, the macroaxis of seeds bigger, ca. 0.5 × 0.3 mm, brownish-black, not appendant, elliptic, both ends pointed.

Preliminary conservation status.

Based on the result of our joint field surveys in the type locality and adjacent regions, the EOO and AOO of Actinostephanus enpingensis are about 79.5 km2 and 0.1 km2, respectively. So far, only one population of this species has been recorded along the local stream in the Qixingkeng provincial natural reserve, Enping city, Guangdong province, southern China, but we believe that more A. enpingensis populations can be found in the hills of Enping and its adjacent counties. If that is the case, the Extent of Occurrence (EOO) and Area of Occupancy (AOO) of this species will increase. Because the flowers and leaves of this species are inconspicuous, and after learning from some local people that it has no known medicinal value we feel that this species faces little risk. Moreover, almost all of these plants are growing in the protected areas of this reserve so that the species are well protected. According to the Guidelines for Using the IUCN Red List Categories and Criteria ( IUCN 2019), we access this taxon as a Least Concern species (LC).

Figures

Figure 3. Photos of Actinostephanus F. Wen, Y. G. Wei & L. F. Fu gen. nov. (A. enpingensis F. Wen, Y. G. Wei & Z. B. Xin sp. nov.), the individuals in natural habitat. A habitat B habit C plant in flowering D plant in fruiting.

Figure 4. Photos of Actinostephanus F. Wen, Y. G. Wei & L. F. Fu gen. nov., the individuals in natural habitat. A. enpingensis F. Wen, Y. G. Wei & Z. B. Xin sp. nov. A top view of plant B upward view of plant for showing root system C top view of bud at the end of root D upward view of bud at the end of root E adaxial surfaces of leaves F abaxial surfaces of leaves G cymes H lateral view of flower I posterior view of flower J frontal view of corolla K stamens and staminodes L abaxial surfaces of calyx lobes M pistil N infructescence O capsule and persistent calyx lobes P opened capsule Q cross-section of capsule R seeds.