Research Article |
Corresponding author: Long Wang ( lwang@scbg.ac.cn ) Academic editor: Alexander Sennikov
© 2022 Wen-Qun Fei, Tao Deng, Long Wang.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Fei W-Q, Deng T, Wang L (2022) Ligularia monocephala (Asteraceae, Senecioneae), a remarkable new species from Hubei, China. PhytoKeys 189: 51-60. https://doi.org/10.3897/phytokeys.189.80016
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Ligularia monocephala, a remarkable new species from Hubei, China, is described and illustrated. It is readily distinguishable in the whole genus by character combination of the reniform to cordate-reniform leaf blades which are palmately-pinnately veined and abaxially purplish red, the solitary and erect capitula, and the pappus which are as long as or slightly longer than tube of the tubular corolla. A detailed description and distribution map of the species are also presented herein.
Compositae, Hubei, Shennongjia, taxonomy
Ligularia Cass., as the largest genus of tribe Senecioneae in Asteraceae in China, consists of approximately 130 species distributed mainly in eastern Asia (
During a field expedition in August 2016 to Shennongjia, Hubei, China, the second author was able to discover a unique Ligularia population in an alpine region of this area. The plant, at first sight, shows an affinity with Ligularia hookeri (C.B. Clarke) Hand.-Mazz. in habit, however, the leaf color and the capitula orientation can easily set them apart. An in-depth survey of herbarium specimens was conducted, resulting in the finding of four gatherings (Anonymous 662, D.G. Zhang 080826018, Z.E. Zhao 1609 and X.L. Yu et al. 080078) all made from Shennongjia, Hubei, China, that are morphologically in conformity with this plant. To precisely decide the identity of these gatherings, we conducted another two field investigations to Shennongjia in September, 2020 and August, 2021, respectively, leading to a better understanding of the variation range of several main morphological characters of this plant. Upon careful observations and comparisons, it was found to be quite different from any other species in the genus in an array of morphological characters. We therefore concluded that this plant represents a hitherto undescribed species, which we describe below.
For morphological comparisons, we critically examined physical or digitalized herbarium specimens with high-resolution of the genus Ligularia at A, BM, CDBI, CSFI, E, GH, HIB, HITBC, HNWP, IBSC, JIU, K, KATH, KUN, LE, NAS, NY, P, PE, S, SZ, W, WU, and WUK (acronyms follow
Readily distinguishable in the whole genus by the character combination of the reniform to cordate-reniform leaf blades which are purplish red abaxially and palmately-pinnately veined, the solitary and erect capitula, and the pappus which are as long as, or slightly longer, than tube of the tubular corolla.
China. Hubei Province, Shennongjia Forest Department, Shennongding Nature Reserve, Shennonggu valley, 31°26'19.36"N, 110°16'26.46"E, 2681 m a.s.l., on cliffs, 12 July 2021, W.Q. Fei & H.S. Wu 324 (holotype: IBSC; isotypes: IBSC, KUN).
Photographs of Ligularia monocephala sp. nov. A portion of stem B leaf blade (adaxial surface) C leaf blade (abaxial surface) D capitulum (top view) E capitulum (side view) F outer phyllaries (abaxial surface) G inner phyllaries (abaxial surface) H ray florets I tubular florets. All photographs by Wen-Qun Fei.
Perennial herb. Stems solitary, erect, 15–20 cm tall, ca. 3 mm in diam. at base, proximal to median part slightly brown puberulent and white arachnoid to glabrescent, distal part densely brownish pilose. Basal leaves ascending, long petiolate; petiole 5–10 cm long, not winged throughout; leaf blade reniform to cordate-reniform, 3.5–4.5(–6) cm long, 3.5–5(–7) cm wide, herbaceous, adaxially dark green, slightly shortly puberulent to glabrescent, abaxially purplish red, brownish puberulent at first, especially along veins, then becoming glabrescent, base cordate, margin regularly dentate, apex rounded or slightly obtuse; sinus narrow, basal lobes nearly rounded, slightly divergent; vein palmate-pinnate; primary veins 3–5. Stem leaves 4–6(–7). Proximal stem leaves usually 1, petiolate; petioles ca. 3 cm long, basally sheathed; sheath usually more or less broadened; leaf blade reniform to cordate-reniform, slightly smaller than basal leaves. Median stem leaves usually 1, nearly sessile; leaf blade usually less than 3 cm long and 3 cm wide; base slightly or enlarged sheathed. Distal stem leaves usually 2–5, much smaller and reduced, bract-like, lanceolate, 6–10 mm long, 1.5–3 mm wide; margin slightly ciliate or entire. Capitula solitary, erect, 5 cm in diam. including ray florets; bracts 1 or 2, lanceolate to subulate, 3–4 mm long, ca. 1 mm wide. Involucres cylindrical, 11–14 mm high, 9–14 mm in diam., outside shortly brownish puberulent; receptacle densely shortly puberulent outside; phyllaries 9–10, spreading, in 2 rows; outer phyllaries narrowly oblong, 2–2.5 mm wide, apex acute; inner phyllaries oblong, ca. 3 mm wide, margin membranous, apex acute to obtuse. Ray florets 6–9, yellow; lamina oblong to elliptic, 3.0–3.5 cm long, 6–7 mm wide, apex acute, 3-denticulate; tube 5 mm long. Tubular florets numerous, yellow, ca. 2 cm long; tube 5 mm long; limb campanulate, 5–7 mm long; style 1.2 cm long. Achenes (immature) oblong, cylindrical, pale yellow, 3–4 mm long, glabrous. Pappus brown in the upper two-thirds, white (distal part) and purplish red (proximal part) in the lower one-third, 5–7 mm long, as long as, or slightly longer, than tube of tubular corolla.
The specific epithet ‘monocephala’ alludes to occurrence of solitary capitulum per stem.
Flowering from July to August; fruiting in September.
China. Hubei: Shennongjia Forest District, Shennongding Scenic Spot, Badongya, on rocky cliffs, 10 July 1987, Anonymous 662 (HIB); Shennongjia Forest District, Shennongding Scenic Spot, Shennonggu valley, on moist cliffs covered by mosses, 31°26'42.95"N, 110°15'49.88"E, 3026 m a.s.l., 22 September 2020, L. Wang, X.Q. Guo & Q.E. Yang 4216 (IBSC); ibid., on cliffs, 2852 m, 9 August 2008, X.L. Yu et al. 080078 (CSFI); Shennongjia Forest District, precise locality unknown, 17 August 2012, D.G. Zhang 080826018 (JIU); Shennongjia Forest District, precise locality unknown, in rock crevices, 2800 m a.s.l., 2 September 1980, Z.E. Zhao 1609 (HIB).
The generic placement of this newly described taxon, which is superficially similar to some species of Cremanthodium in the general habit (the gatherings Anonymous 662, D.G. Zhang 080826018, and Z.E. Zhao 1609 were, in fact, previously identified on the determination slips as species of Cremanthodium), is worthy of detailed remarks. The independent generic status of Cremanthodium, the putatively closest ally of Ligularia, has been widely accepted in recent checklists or Floras at the national level (e.g.
In the genus Ligularia, L. monocephala is tentatively assigned to L. sect. Corymbosae (Franch.) Hand.-Mazz. ser. Retusae S.W. Liu due to its palmate-pinnate leaf venation, lanceolate to subulate bract, and cylindrical involucre. Within this series, it resembles L. phoenicochaeta (Franch.) Hand.-Mazz. to some extent, but differs mainly by the abaxially purplish red (vs. pale green) leaf blades (Fig.
Differences among Ligularia hookeri, L. jamesii, L. monocephala and L. phoenicochaeta.
L. hookeri | L. jamesii | L. monocephala | L. phoenicochaeta | |
---|---|---|---|---|
Stems | distally white arachnoid and shortly brown pilose | distally white arachnoid-puberulent | densely brownish pilose | distally shortly brown pilose |
Basal leaves | leaf blade cordate-sagittate or reniform, abaxially pale green, rarely purplish red; margin triangularly or coarsely dentate, between teeth shortly pilose, apex rounded; palmately veined | leaf blade triangular-hastate, abaxially pale green; margin sharply dentate, apex acute or acuminate; palmately-pinnately veined | leaf blade reniform to cordate-reniform, abaxially purplish red; margin regularly dentate, apex rounded or slightly obtuse; palmately-pinnately veined | leaf blade orbicular-reniform, abaxially pale green; margin regularly triangular-dentate, apex rounded; palmately veined |
Capitula | usually solitary, sometimes 2–7(–16) arraged in a raceme; cernuous to horizontal | solitary; erect | solitary; erect | usually solitary, sometimes 2–4 arranged in a lax corymb; cernuous |
Involucres | campanulate, 6–8(–10) mm in diam., outside shortly brown pilose or glabrous | broadly campanulate, to 1.5 cm, outside white arachnoid-puberulent | cylindrical, 9–14 mm in diam., outside shortly brownish puberulent | hemispheric, to 24 mm in diam., outside glabrous |
Ray florets | lamina linear, 1.5–2 mm wide | lamina linear-lanceolate, 3–4 mm wide | lamina oblong to elliptic, 6–7 mm wide | lamina elliptic or oblong-lanceolate, ca. 2 mm wide |
Pappus | brown or pale brown, 6–7 mm long, as long as tubular corolla | pale yellow, 7–8 mm long, as long as tubular corolla | brown in the upper two-thirds, white (distal part) and purplish red (proximal part) in the lower one-third, 5–7 mm long, as long as or slightly longer than tube of tubular corolla | purplish brown, 1–2 mm long, much shorter than tube of tubular corolla |
Distribution in China | Shaanxi, Sichuan, Xizang, Yunnan | Jilin, Liaoning, Nei Mongol | Chongqing, Hubei | Yunnan |
We would like to thank Dr. Chen Ren and Dr. Alexander Sennikov for their constructive suggestions. We are grateful to the curators of A, BM, CDBI, CSFI, E, GH, HIB, HITBC, HNWP, IBSC, JIU, K, KATH, KUN, LE, NAS, NY, P, PE, S, SZ, W, WU, and WUK for allowing us to use their scanned images of specimens and for research facilities. Thanks are also given to Mr. Xin-Qiang Guo, and Mr. Hai-Song Wu for field assistance. This work was supported by the National Natural Science Foundation of China (grant no. 31900183), the Biological Resources Programme of the Chinese Academy of Sciences (grant no. KFJ-BRP-017-08), Key Laboratory of Conservation Biology of Golden monkey in Shennongjia of Hubei Province (grant no. SNJGKL202002), the Youth Innovation Promotion Association of Chinese Academy of Sciences (grant no. 2019382), and the Ten Thousand Talents Program of Yunnan Province (grant no. 202005AB160005).