Silene ophioglossa Huan C. Wang & Feng Yang, 2023

Yang, Feng, Wang, Ting-Ting, Wang, Yue-Hua & Wang, Huan-Chong, 2023, Silene ophioglossa (Caryophyllaceae, Sileneae), a new species from southwest China, PhytoKeys 225, pp. 99-113 : 99

Silene ophioglossa Huan C. Wang & Feng Yang sp. nov.

Figs 1 , 2

Type.

China. Yunnan Province: Binchuan County, Pingchuan Town, Maojiaoshan Mountain , alt. 2198 m, 25°58'13.6"N, 100°42'8.28"E, under a walnut forest by a ravine stream, 17 June 2022, F. Yang et al. BC17342 (holotype YUKU-02074705!; isotypes YUKU-02074706!, PE!, HITBC!) .

Diagnosis.

Silene ophioglossa is morphologically similar to S. phoenicodonta (Fig. 3 ), but clearly differs from the latter in having 5-7 mm (vs. 6-8 mm) long calyces sparsely hirtellous and short glandular hairs (vs. densely hirtellous and with short glandular hairs), white (vs. dark violet) petals, linear (vs. obovate) limbs and linear (vs. ovate or nearly band-shaped) lobes, absent or oblong-linear (vs. orbicular-linear) coronal scales.

Etymology.

The specific epithet " ophioglossa " is derived from the Greek words " ophis " (meaning snake) and " glossa " (meaning tongue), which refer to the petal lobes of this new species which resemble the tongue of a snake.

Description.

Herbs perennial. Roots numerous, clustered, cylindric, fleshy. Stems sparsely caespitose, ascending to sprawling, 30-80 cm long, slender, multibranched, with sparsely pubescent. Leaves ovate-elliptic or obovate-elliptic, 3-9 (-15) cm long, 1-4 cm wide, base cuneate or attenuate into petiole, apex acute, both surfaces puberulent to subglabrous, margin entire, minutely ciliate, lateral veins 2 pairs, midrib and lateral veins prominent abaxially. Dichasial cymes terminal, diffuse; peduncle 1-15 cm long, densely glandular-pilose. Pedicels densely glandular-pilose and sparsely eglandular villous, subequaling or longer than calyx; bracts ovate-lanceolate, apex acuminate. Calyx tubular-campanulate, 5-7 mm long, 2-3 mm in diameter, longitudinal veins green or violet, cohering at apex, sparsely hirtellous and with short glandular hairs, inflated after anthesis, 6-7 mm long, 4-5 mm in diameter in fruit stage; calyx teeth ovate-triangular, green or violet, ca. 1 mm long, apex acute, margin ciliate. Androgynophore ca. 1 mm long, glabrous. Petals white, 1.0-1.2 cm long; claws equaling to calyx, oblanceolate, glabrous, inflated above, margin erose; limbs linear, deeply bifid to middle, lobes linear, apex usually curly, without side lobe; coronal scales absent or oblong-linear, small, entire or emarginated at apex. Stamens 10, included in calyx tube; filaments glabrous, 5-7 mm long. Styles 3, included or slightly exserted beyond calyx. Capsule broadly ovoid, 7-9 mm long, 4-5 mm in diameter, slightly longer than calyx. Seeds dark brown, globose-reniform, ca. 1 mm long, tuberculate.

Molecular phylogenetics.

The ITS sequence region of Silene ophioglossa comprises 687 and 821 base pairs with a GC content of 53.3% and 54.4%. The alignment of 73 ITS sequences resulted in a matrix of 582 total characters, 350 of which are constant, 58 of the variable characters are singleton sites and 174 characters are parsimony-informative sites.

Phylogenetic analyses using ITS sequences uncovered that the new species, S. ophioglossa , belongs to a clade A representing S. sect. Cucubaloides Edgeworth & Hook. f. which was recircumscribed by Jafari et al. (2020) in their recent studies (Fig. 4 ). This placement is also supported by its morphological characters, such as the ascending to sprawling, multibranched stems, ovate-elliptic or obovate-elliptic leaves, lax dichasial cymes and tubular-campanulate calyces. In the phylogenetic tree (Fig. 4 ), two sequences from S. ophioglossa constituted a monophyletic lineage with maximum support, and it is sister to a small subclade B that includes S. phoenicodonta and S. viscidula . This close relationship is also supported by their morphological similarity.

Seed micromorphology.

Seeds of Silene ophioglossa are dark brown when mature, globose-reniform in shape, 0.94-1.12 mm long, 0.79-0.94 mm wide. The lateral surface of seed is concave. The dorsal surface is flat, ca. 0.57 mm wide. Its seed coat is formed by elongate epidermis cells with S-undulate and V-undulate anticlinal walls. The periclinal walls are convex and have granulate-papillate ornamentation (Fig. 5A-C ).

Phenology.

Flowering and fruiting from June to September.

Distribution and habitat.

Silene ophioglossa is endemic to southwest China, where it has been collected from western Sichuan and north Yunnan (Fig. 6 ). Currently, it seems to be restricted to the Jinsha River basin. Silene ophioglossa usually occurs at elevations ranging from 2000-3000 meters and grows in thickets or at forest margins, and its association includes Lepisorus palmatopedatus (Baker) C. F. Zhao, R. Wei et X. C. Zhang, Lysimachia christiniae Hance, Corydalis triternatifolia C. Y. Wu, Indigofera pendula Franch., Lysimachia stenosepala Hemsl. var. flavescens Chen et C. M. Hu, Circaea cordata Royle, Quercus acutissima Carr. and Campylotropis teretiracemosa P. C. Li et C. J. Chen.

Conservation status.

Silene ophioglossa is known from five localities and has been found in thickets or at forest margins. However, we actually only investigated two points, and didn’t have enough information about its distribution, abundance, or threats to this species. More information is needed for assignment of its conservation status. Therefore, we choose to assign this new species to the category data deficient (DD) following the IUCN guidelines ( IUCN 2012, 2022).

Taxonomic notes.

Morphologically and seed micromorphologically, Silene ophioglossa is most similar to S. phoenicodonta (Fig. 3 ), a species also distributed in southwest China (Fig. 6 ). They share ascending to sprawling, multibranched stems, ovate-elliptic or obovate-elliptic leaves, dichasial cymes, 3 styles and globose-reniform seeds (Fig. 5 ), but the new species is distinguishable from the latter by its calyces 5-7 mm (vs. 6-8 mm) long, sparsely (vs. densely) hirtellous and with short glandular hairs, petals white (vs. dark violet), limbs linear (vs. obovate), lobes linear (vs. ovate or nearly band-shaped) and coronal scales absent or oblong-linear (vs. orbicular-linear).

Silene ophioglossa is somewhat close to S. viscidula , an endemic species found from southwestern China. Nevertheless, S. ophioglossa differs from S. viscidula in having ovate-elliptic or obovate-elliptic (vs. elliptic or elliptic-oblanceolate) leaves, diffuse (vs. compact, 3-7 (-15)-flowered) dichasia, 5-7 mm long (vs. 7-10 mm long) calyces, sparsely hirtellous and with short glandular hairs (vs. densely glandular hairs), white (vs. pale pink or white) petals, linear (vs. broadly obovate) limbs, linear (vs. ovate or square) lobes, absent or oblong-linear (vs. flabellate) coronal scales. A detailed morphological comparison between these three species is summarized in Table 1 .

Additional specimens examined (Paratypes).

China. Sichaun: Muli County, Qiaowa Town, Chutouwan village , under the shady and moist thickets by the river, alt. 2600 m, 28 June 1978, Y. B. Yang 7097 (CDBI-0020627, CDBI-0020628); Muli County , Ninglang village , under Tsuga forest on the mountain slope, alt. 3000 m, 25 September 1983, Qinghai-Tibet Expedition 14350 (KUN-0514408, KUN-0514409) . Yunnan: Luquan County, Sayingpan Town, Sayongshan Mountain , at evergreen broad-leaved forest margins, alt. 2400 m, 21 June 1965, W. M. Zhu & Y. M. Feng 00584 (YUKU-02006723); Xiangyun County , Midian Town , Yemaoshan Mountain , alt. 2300 m, 25°41'52.12"N, 100°49'26.69"E, 24 July 2018, Xiangyun Medicinal Plant Investigation Team 5329230617 (YUKU-02074711, YUKU-02074712, YUKU-02074713) and F. Yang et al. XY8075 (YUKU-02074710); same location, 26 August 2019, Q. P. Wang et al. XY7908 (YUKU-02074714, YUKU-02074715) .

Silene phoenicodonta . China. Sichaun: Zhaojue County, Sikai Town, thickets, alt. 2400 m, 30 June 1976, Sichuan Vegetation Team 12763 (PE-00580695, CDBI-0020501). Yunnan: Huizhe County , Dahai village , Dahaicaoshan , ca. 2 km from Xiaoxiniu , Dabaping , alpine meadows, 103°16'10.50"E, 26°12'6.19"N, alt. 3433 m, 24 July 2018, H. Tang TH2018046 (KUN-1481546); Dongchuan District , Xueling Scenic Area , 29 August 2017, D. Qiao DC2575 (YUKU-02074716); Heqing County , Songgui Town , Maershan Mountain , on the path from Chamujing to Zhulinkou, under forest, roadsides, 100°7'53.68"E, 26°23'2.58"N, alt. 2578 m, 5 August 2018, H. Tang TH2018087 (KUN-1481543); Jianchuan County , Shizhongshan Mountain , July 1987, S. Y. Bao 401 (KUN-0531671); Zhengkang County , Snow Range, in grassy slope, alt. 2600 m, 22 July 1938, T. T. Yu 16881 (PE-00558309, KUN-0514405) .

Silene viscidula . China. Sichaun: Yanbian County, Dapingzi District, Baoshishan , limestone mountainous region, at 2700 m, 29 June 1983, Qinghai-Tibet Team 11677 (KUN-0514407) . Guizhou: Weining County, Mazha Town, Gali village , Mabaidashan , 12 July 1959, Bijie Team 191 (PE-00581476) . Yunnan: Luquan County, Kedu Town, Dianwei village , grassy slope, at 2500 m, 25 October 1940, Y. B Chang 347 (IBSC-0149532); Dongchuan District , November 1906, E. E. Maire 87 (E-00109656); Mengzi, Yangliuhe village , sparse forest, at 1720 m, 30 July 1958, Y. Y. Hu & S. K. Wen 580546 (KUN-0514415) .

Figures

Figure 1. Silene ophioglossa sp. nov. (Drawn by Tingting Wang) A habit B flower (front view) C adaxial surface of leaf D petal E pistil and androgynophore F seed.

Figure 2. Silene ophioglossa sp. nov. (Photographed by F. Yang) A habit B abaxial surface of leaf C adaxial surface of leaf D roots E dichasial cymes F flower (side view, showing the calyx) G flower (front view) H dissected flower (showing the androgynophore and claws) I pistil and androgynophore J petal (showing the claw, auricles and coronal scales) K immature capsule L seeds.

Figure 3. Silene phoenicodonta (Photographed by F. Yang and H. C. Wang) A habit B adaxial surface of leaf C abaxial surface of leaf D dissected flower (showing the androgynophore and claws) E roots F flower (side view, showing the calyx and pedicel) G flower (front view) H petal (showing the claw, auricles and coronal scales) I styles and immature capsule J calyx after anthesis K seeds.

Figure 4. Bayesian inference tree of Silene based on ITS sequences showing phylogenetic placements of S. ophioglossa. Bayesian posterior probabilities are shown near the nodes. Silene ophioglossa, S. viscidula and S. phoenicodonta are marked in bold type, and S. ophioglossa is highlighted by using red colored text.

Figure 5. SEM micrographs of seed morphology in Silene ophioglossa (voucher specimen: Q. P. Wang et al. XY 7908, A-C) and S. phoenicodonta (voucher specimen: D. Qiao DC 2575, D-F). A, D lateral surface B, E dorsal surface C, F ventral surface.

Figure 6. Distribution of Silene ophioglossa and S. phoenicodonta in southwest China.