Oreocharis polyneura Y.H.Tan, F.Wen & Y.X.Gong, 2022

Gong, Yan-Xiong, Ding, Hong-Bo, Yan, Xiang-Shuai, Wen, Fang, Tian, Yao-Hua & Tan, Yun-Hong, 2022, Oreocharis polyneura, a new species of Gesneriaceae from southern Yunnan, China, PhytoKeys 214, pp. 7-15 : 7

Oreocharis polyneura Y.H.Tan, F.Wen & Y.X.Gong sp. nov.

Figs 1 , 2

Diagnosis.

Oreocharis polyneura is similar to O. rhytidophylla in having more obvious lateral veins forming crosslinked network on the adaxial surface of leaf blades, but can be distinguished by having more lateral veins (12-15 pairs vs. 7-9 pairs) of leaf blades, shorter corolla tubes (the length ratio of corolla tube to corolla lobes = 1.2-2.9 vs. 3.4-6) and shorter pistils (6-8 mm long vs. 27-30 mm long).

Type.

China. Yunnan Province, Puer City, Lancang County, Zhutang Town , on rocks or cliffs in evergreen broad-leaved forests in ravines, 22°45'44.28"N, 99°43'26.81"E, elev. 2137 m, 29 July 2021, Y.X. Gong G344 (holotype: HITBC0079099; isotypes: HITBC, IBK). Fig. 2 .

Description.

Perennial herbs. Rhizomes subterete, short, straight, with numerous fibrous roots. Leaves basally forming a rosette, 4-8, petiolate; petioles terete, 1.2-7.0 cm long, 3-5 mm in diameter, densely rust-brown pannose, leaf blade thickly chartaceous, elliptic to ovate-elliptic, 4-13 × 2-7 cm, apex rounded, base rounded to subcordate, margin serrate to crenate, adaxially green, glabrous, abaxially whitish-green, densely rust-brown pannose along veins, lateral veins 12-15 on each side of the midrib, adaxially conspicuously sunken, abaxially conspicuously prominent, anastomosed forming on both surfaces. Inflorescences cymose, axillary, 2-4, 2-4-branched, 4-10-flowered; peduncles 4.5-9.0 cm long, ca. 1-3 mm in diameter, rust-brown lanate; bracts 3, verticillate, each 8.5-9.5 × 3.2-4.2 mm, lanceolate to elliptic, margins usually entire, occasionally 2-3-denticulate, adaxially glabrous, abaxially rust-brown pannose; pedicels 1.0-3.5 cm long, ca. 1 mm in diameter, sparsely puberulent. Calyces actinomorphic, 5-parted from the base, segments equal, linear-lanceolate, 7.5-9.0 × 1.5-2.5 mm, margin dentate, adaxially glabrous, abaxially rust-brown pannose. Corollas yellow, 1.8-2.2 cm long, outside glabrous, inside sparsely glandular-puberulent in the throat on adaxial lobes; tube narrowly infundibuliform, slightly bent near the throat, 1-1.5 cm long, 4-5.5 mm in diameter, proximally and distally almost equal in width; limb indistinctively bilabiate, adaxial lip 2-lobed, lobes obovate to elliptic, 5.8-6.2 × 3.8-4.8 mm, apex obtuse, margin entire, abaxial lip 3-lobed, lobes obovate to elliptic, almost equal, 6.2-8.2 × 5.2-6.2 mm, apex rounded, margin entire. Stamens 4, included, two pairs of stamens cohering at the anther tips, adnate to corolla tube 4-6 mm from base; adaxial stamens 3.5-4.5 mm long, abaxial stamens 5-6 mm long; filaments yellow, linear, glabrous; anthers basifixed, reniform, 2-locular, dehiscing transversely; staminode 1, 1.4 mm long, adnate to corolla tube 1.8 mm from the base. Pistils 6-8 mm long, glabrous; ovary 5-6.5 mm long, ca. 1.5 mm in diameter, glabrous, with two parietal placentae; style 1-1.5 mm long; stigma 1, disciform, retuse, edge flipped outwardly, 1.5-2.0 mm in diameter. Discs ring-shaped, ca. 2.3 mm high, margin slightly undulate with 5 irregularly and shallow lobes. Capsules indistinctively 4-angled to subterete, ca. 4 cm long, ca. 3 mm in diameter, glabrous.

Phenology.

Flowering from July to October; fruiting from September to November.

Etymology.

Greek polys, many, and neuron, nerve, alluding to abaxially conspicuous lateral leaf veins

Habitat and distribution.

Endemic to Zhutang town, Lancang county, Puer city, Yunnan Province, China (Fig. 4 ). It grows on rocks or cliffs under evergreen broad-leaved forests in ravines at elevations of 1900-2200 m.

Conservation status.

Oreocharis polyneura is currently known only from its type locality. Based on our present knowledge and available data, its conservation status is assessed as "Data Deficient" (DD; IUCN 2019).

Vernacular name.

The Chinese name of the new species is "Duō Mài Mǎ Líng Jù Tái” (多脉马铃苣苔). The first two words, Duō Mài mean the numerous veins of the leaf blades, and the rest four words mean the genus Oreocharis in mandarin.

Notes.

Morphologically, Oreocharis polyneura is most similar to O. rhytidophylla in its leaves and inflorescences but is readily distinguishable by an array of characters (see Table 1 ).

Figures

Figure 1. Oreocharis polyneura Y. H. Tan, F. Wen & Y. X. Gong, sp. nov. A habit B inflorescence C behind view of flower D fruit E whole plant F inflorescence with scale G adaxial and abaxial leaf surfaces H bracts I, J calyces K opened corolla showing stamens and staminode L pistil with disc and calyces M cross section of fruit. Photographed by Yan-Xiong Gong.

Figure 2. Type sheet of Oreocharis polyneura Y. H. Tan, F. Wen & Y. X. Gong, sp. nov.

Figure 4. Distribution of Oreocharis polyneura (black triangle) and O. rhytidophylla (black circle).