Gentiana mopanshanensis Huan C. Wang & Tao Chen bis, 2024

Chen, Tao, Wang, Ting-Ting, Liu, Shao-Yun & Wang, Huan-Chong, 2024, Gentiana mopanshanensis (Gentianaceae), a new species from Yunnan, southwest China, PhytoKeys 239, pp. 215-228 : 215

Gentiana mopanshanensis Huan C. Wang & Tao Chen bis sp. nov.

Figs 1 , 2 , 3

Type.

China. Yunnan Province: Xinping County, Mopanshan Mountain , near the top of mountain, alt. 2480 m, 23°56′23″N, 101°59′23″E, 3 April 2023, in flower, H. C. Wang et al. XP19775 (Holotype: YUKU!; isotypes: YUKU!) .

Diagnosis.

Gentiana mopanshanensis is distinguishable from all other similar species of the genus by the combination of its rosulate basal leaves lanceolate to gladiate, up to 5 (6) cm long, cauline leaves lanceolate or linear-lanceolate, throat of corolla blue maculate, plicae with 5-10 fimbriations, and fimbriation irregular in length, usually 0.5-2 mm long.

Etymology.

The specific epithet " Gentiana mopanshanensis " is derived from the type locality of the new species, the Mopanshan Mountain, and the Latin suffix - ensis, indicating the place of origin or growth.

Description.

Biennial herbs, diffuse, 5-15 cm in height. Root slightly fleshy, 4-6 cm long, with conspicuous rootstock. Stems yellow-green or purplish-red, smooth, much branched at base; branches procumbent or ascending. Basal leaves rosulate, persistent at anthesis, sessile or subsessile; blades lanceolate to gladiate, (1-) 3-5 (-6) cm long, 0.2-0.7 (-1) cm wide, both surfaces densely and minutely papillate, apex acuminate, margin transparent, densely denticulate, basal veins 1-3, distinct, midvein convex beneath. Cauline leaves opposite, semiamplexicaul, base proximally compounded, petiole tube 1-1.5 mm long; blades lanceolate or linear-lanceolate, 0.3-2 cm long, 0.1-0.6 cm wide, apex acuminate, margin transparent, densely denticulate, both surfaces densely and minutely papillate, basal veins 1-3, midvein convex beneath. Flowers solitary, terminal on branch. Pedicels yellowish green, glabrous, 3-12 mm long, purplish-red striped. Calyx 5-8 mm long, obconic, yellow-green; tube campanulate, 4-5 mm long, 2-3 mm in diameter, slightly longer than lobes; lobes 5, acicular or subulate, 1.5-3 mm long, papillate on margin; veins ridged on abaxial surface, decurrent towards calyx tube; sinus between lobes obtuse to sub-rounded. Corolla 8-14 mm long, 5-8 mm in diameter, trumpet-shaped, blue-white, outside with copper-green stripes, inside with deeply blue spots in throat; tube tubular, 5-8 mm long, 4-6 mm in diameter, golden inside; lobes ovate to broadly ovate, 2-3 mm long, 2-3 mm wide, apex acute, margin entire; plicae triangular-ovate, 2-2.5 mm long, apex irregularly laciniate, fimbriate, with 5-10 fimbriations, usually 0.5-2 mm long. Stamens 5, filaments filiform-subulate, 3-6 mm long, inflated at middle, inserted in lower middle of corolla tube; anthers rectangular-rounded, 0.6-1 mm long. Ovary stipitate, ellipsoid or fusiform, 2.5-3 mm long, apex obtuse, base attenuate; style clavate, 0.5-1 mm long, stigma bifid, extrorse. Capsules obovate, exerted beyond persistent corolla, gynophore up to 15 mm long, narrowly winged on both margins. Seeds ovate-triangular, up to 1.5 mm long, yellowish-brown, densely striato-reticulate on seed coats.

Phenology.

Gentiana mopanshanensis has a long flowering and fruiting period. It starts flowering in March and continues until August, and its fruiting period is from May to September.

Distribution and habitat.

Gentiana mopanshanensis is currently only found in the Mopanshan Mountain (Fig. 4 ), which is located in the southeast of Xinping County, at the southwestern edge of the Yunnan-Guizhou Plateau. The mountain is situated east of the Yuanjiang River valley and has an elevation ranging from 1370 to 2611 meters. G. mopanshanensis usually occurs at elevations between 2400 and 2550 meters and mainly grows in wet meadows near the peak of the mountain. It can also be occasionally found under the thickets predominated by Lithocarpus variolosus Chun ( Fagaceae ) and Quercus guyavifolia H. Lév. ( Fagaceae ). In meadow habitats, this new species is commonly associated with G. praticola Franchet ( Gentianaceae ), Polygala dunniana H. Lév. ( Polygalaceae ), Arundinella hookeri Munro ex Keng ( Gramineae ), Fragaria nilgerrensis Schlecht. ex J. Gay ( Rosaceae ), Roscoea tibetica Batalin ( Zingiberaceae ) and Bistorta paleacea Yonek. et H.Ohashi ( Polygonaceae ).

Molecular phylogenetics.

The ITS sequence region of Gentiana mopanshanensis comprises 625 base pairs with a GC content of 57.12%. The alignment of 60 ITS sequences resulted in a matrix of 662 total characters, of which 344 are constant, 93 of the variable characters are singleton sites and 225 characters are parsimony informative sites.

As shown in the phylogenetic tree (Fig. 5 ), phylogenetic analyses using the ITS sequence data demonstrated that the new species belongs to a clade representing the Gentiana section Chondrophyllae with maximum support. In this clade, G. mopanshanensis falls within the subclade corresponding to series Fimbriata Marq. with 0.993 posterior probabilities. It constituted a monophyletic lineage with G. panthaica Prain et Burkill and G. mairei H. Lév. with maximum support (PP = 1) and were resolved as sister to them. The phylogenetic result is also supported by the morphological characteristics.

Discussion.

Based on phylogenetic analyses, Gentiana mopanshanensis should be assigned to the series Fimbriatae of the section Fimbriatae Chondrophyllae . Its placement within this series is also supported by its particular morphological characters: stems much branched at the base, basal leaves well developed, leaf blades and calyx with densely and minutely papillate, calyx lobes acicular or subulate, plicae apex fimbriate, obovate capsule with strong and broad wings at apex.

This new species is most similar to Gentiana mairei and G. panthaica in terms of habit, and flower shape and size, especially plicae apex fimbriate. However, G. mopanshanensis can be distinguished from G. mairei by its biennial (vs. annual) habit, basal leaves lanceolate to gladiate (vs. ovate to ovate-elliptic), (1-) 3-5 (-6) cm (vs. 0.7-1.4 cm) long, 0.2-1 cm (vs. 0.3-0.7 cm) wide, cauline leaves lanceolate or linear-lanceolate (vs. ovate-triangular to ovate-lanceolate), with blue spots (vs. blackish, white or pale yellow stripes) in throat, plicae with 5-10 (vs. 8-10) fimbriations, irregular (vs. nearly equal) in length, ususally 0.5-2 mm (vs. 2-2.5 mm) long. G. mopanshanensis differs from G. panthaica in biennial (vs. annual) habit, basal leaves lanceolate to gladiate (vs. ovate-elliptic to ovate), cauline leaves lanceolate or linear-lanceolate (vs. lanceolate, narrowly elliptic or ovate-triangular), plicae with 5-10 (vs. 15-20) fimbriations, filament laciniate (vs. filiform, curly). A detailed morphological comparison between these three species is summarized in Table 1 .

Additional specimens examined.

Gentiana mopanshanensis. China. Yunnan: Xinping County, Mopan Mountain, alt. 2509 m, 13 August 2012, in flower and fruit, Xinping County Census team 5304270757 (IMDY0019083); same location, alt. 2406 m, 18 June 2023, in flower and fruit, T. Chen et al. XP23338 (YUKU) .

Gentiana mairei . China. Yunnan: Dali City, Cangshan Mountain , alt. 3800 m, 22 July 2009, Z.J.Yin et al. 1631 (KUN-1220364); Jingdong County, Wuliangshan Mountain , alt. 3100 m, 19 November 1956, B.Y.Qiu 53823 (KUN-00088281) .

Gentiana panthaica . China. Yunnan: Heqing County, Mae Shan, 15 August 2020, Q.P. Wang et al. HQ 8930 (YUKU); Nanjian County , Wuliangshan Mountain , alt. 2270 m, 24 March 2012, E.D. Liu et al. 3587 (KUN-1224606); Dali City, Cangshan Mountain , alt. 3800 m, 15 July 2009, Z.J.Yin et al. 1362 (KUN-1220362); same location, 13 July 2009, Z.J.Yin et al. 1111 (KUN-1220361); Luquan County , Daheiqing, alt. 3150 m, 2 July 1990, R.F.Fang et al. 83 (KUN-551847) .

Figures

Figure 1. Gentiana mopanshanensis sp. nov. (Drawn by Ting T. Wang) A habit B flower (front view) C dissected corolla D dissected calyx E seed.

Figure 2. Gentiana mopanshanensis sp. nov. (Photographed by HCW and TC) A habitat B habit C root D leaf blade (side view, showing adaxially densely and minutely papillate and transparent denticulate on margin) E closed flower F flower (front view) G dissected flower (showing the stamens and style) H mature fruit protruding from persistent corolla I stamens J pistils K seed.

Figure 3. Holotype of Gentiana mopanshanensis sp. nov. (YUKU- 05008414).

Figure 4. Geographical distribution of Gentiana mopanshanensis sp. nov. (red dot).

Figure 5. Mrbayes tree of Gentiana based on ITS sequences showing phylogenetic placement of G. mopanshanensis. Mrbayes posterior probabilities are shown near the nodes. G. mopanshanensis is marked by a red box.