Chrysanthemumdabieshanense, a new name for Chrysanthemumvestitum var. latifolium (Asteraceae, Anthemideae)

Abstract

Recent phylogenetic analyses have revealed that Chrysanthemumvestitumvar.latifolium and C.vestitumvar.vestitum were placed in different clades based on their chloroplast genomes and nuclear LFAFY gene sequences. Accordingly, based on previous morphological analysis, molecular phylogenetic results, fieldwork, and herbarium studies, Chrysanthemumvestitumvar.latifolium should be raised to the species level. Considering the condition of the material found and Articles 6.9, 6.11, 41.2, 58.1 of the International Code of Nomenclature for Algae, Fungi, and Plants (Shenzhen Code) that is currently in force, Chrysanthemumdabieshanense Z.X.Fu, A.G.Zhen, & Y.P.Ma, nom. nov. is proposed as the new name for Chrysanthemumvestitumvar.latifolium J.Zhou & Jun Y.Chen. The detailed emended description, distribution map, insights into its habitat, and an updated comparative morphological study are presented in this study.

Introduction

Chrysanthemum L. is a genus of the tribe Anthemideae that contains approximately 40 species. This genus is mainly distributed in temperate Asia (Oberprieler et al. 2007), with approximately 23 species in China (Shih et al. 2011; Meng et al. 2020). The genus is characterized by subshrubs or perennial herbs with pinnately or palmately divided alternate leaves, female ray florets, white or red apical appendages of anthers, and faintly 5–8-ribbed achenes (Shih et al. 2011). Furthermore, recent molecular phylogenetic studies have demonstrated that Chinese Chrysanthemum should be divided into two groups: the Chrysanthemumzawadskii group, which is distributed in northern China and has erect stems and large capitula with white or purple ray florets, and the Chrysanthemumindicum group, which is distributed from north to south China and has creeping stems and capitula with yellow or white ray florets (Liu et al. 2012; Li et al. 2014; Ma et al. 2020).

According to the phylogenetic study of chloroplast genomes and the nuclear LFAFY gene by Ma et al. (2020), Chrysanthemumvestitumvar.vestitum from the Funiu Mountain in Henan Province and C.vestitumvar.latifolium from the Tianzhu Mountain in Anhui Province represent two distinct clades. Morphologically, C.vestitumvar.latifolium is not similar to other species of Clade I (Shih et al. 2011). Accordingly, based on the morphological and molecular results, we propose that the variety Chrysanthemumvestitumvar.latifolium should be raised to the species level.

This evidence of phylogenetic results seems to be sufficient for a new taxonomic decision. This study aimed to describe one of the species of Chrysanthemum and investigate its phylogenetic affinities based on molecular and morphological data. Combined with previous morphological and field studies, we also provide a distribution map and information on the taxonomy of Chrysanthemumdabieshanense.

Materials and methods

We employed standard techniques for morphological studies of herbarium specimens and digital images of the most closely related species from the herbaria CSH, HIB, K, KUN, PE, WUK; acronyms follow Thiers (2022), including the holotype specimens of Chrysanthemumvestitum (Hemsl.) Stapf (Fig. 1A) (K, images seen). Dr Z.X. Fu visited the PE herbarium (Institute of Botany, Chinese Academy of Sciences) in June 2021 and compared and checked the holotype specimen of Chrysanthemumvestitum(Hemsl.)Stapf.var.latifolium J.Zhou et J.Y.Chen (East China Station Inst. Bot. 6935, Fig. 1B, PE). We also verified that morphological characteristics of voucher specimen MYP-20160826 (Fig. 2, Ma et al. 2020, photo from Y.P. Ma) are identical to those of the type specimen of C.vestitumvar.latifolium.

Figure 1.

The images of the holotype of Chrysanthemumvestitum and Chrysanthemumvestitum(Hemsl.)Stapf.var.latifoliumA the lectotype of Chrysanthemumvestitum (Hemsl.) Stapf. Image courtesy of the Royal Botanic Gardens, Kew (K). (Type: China. Hubei: Yichang city, “Ichang and immediate neighborhood”, Sep 1886, A. Henry 1115 lectotype, K000891712) B the holotype of Chrysanthemumvestitum(Hemsl.)Stapf.var.latifolium J.Zhou et J.Y.Chen. Image courtesy of the Herbarium PE, (Type: China, Anhui Province: Yuexi County, Baojia River, alt. 1500 m, 24 Sep 1953, East China Station Inst. Bot. 6935 holotype, PE 00544099!).

Figure 2.

A plant of Chrysanthemumvestitum(Hemsl.)Stapfvar.latifolium collected at Tianzhu Mountain, Dabieshan mountains (The voucher no. MYP-20160826, WUK, Ma et al. 2020) A plant growing in natural habitat B the adaxial side of leaf C the abaxial side of leaf. Scale bar: 2 cm (B, C). Photographed by Yue-ping Ma.

The morphological characteristics of C.vestitumvar.latifolium and its related species were examined for comparative research based on measurements of herbarium specimens (Table 1), supplemented by photos of mature living plants collected from the field (photos from A.G. Zhen and X.X. Zhu). The localities were sorted according to county-level administrative divisions of the People’s Republic of China.

Table 1.

Comparative measurements in Chrysanthemumdabieshanense (= C.vestitumvar.latifolium) and its related species (based on Shih et al. 2011 and additional specimens at the herbaria visited).

	C.dabieshanense	C.vestitumvar.vestitum	C.mongolicum (Clade I)	C.indicum (Clade I)	C.zawadskii (Clade I)	C.lavandulifolium (Clade I)
Leaf blades	orbicular or ovate-orbicular, 4–7 × 3–5 cm, obtusely 2- or 3-lobed	ovate, broadly ovate, oblong, 3.5–7 cm × 2–4 cm, margin repand-dentate	broadly ovate or elliptic 1–2 cm × 1.5–1.8 cm, bipinnatisect	ovate, long ovate, or elliptic-ovate,3–7 cm × 2–4m, bipinnatisect	ovate, broadly ovate, 1.4–4 ×1–3.5 cm, bipinnatisect	ovate, broadly ovate, elliptic-ovate, narrowly elliptic, 2–7 × 1.5–4.5 cm, bipinnatisect
Phyllaries	4 rows	4 rows	5 rows	5 rows	4 rows	5 rows
Capitula	4.5–5 cm in dia.	2–3 cm in diam.	3–4.5 cm in diam.	2.5–4 cm in diam.	1.5–4.5 cm in diam.	1–1.5 cm in diam.

Results and discussion

Zhou and Chen (2010) reported a new variety: Chrysanthemumvestitum(Hemsl.)Stapf.var.latifolium J.Zhou et J.Y.Chen from China (Fig. 1B). In their study, the holotype specimen of Chrysanthemumvestitumvar.latifolium was collected from the Tianzhu Mountain (Anhui Province, Fig. 1B). The variety Chrysanthemumvestitumvar.latifolium is mainly distributed on the western slopes of the Dabie Mountains, throughout the Anhui and Hubei provinces (Qi et al. 2021). It has long been treated as a variety of Chrysanthemumvestitum (Fig. 1A). Based on a recent study by Meng et al. (2020), principal component analysis of leaf length (L), leaf width (W), petiole length (P), and relative petiole length (B = P/L) between C.vestitum and C.vestitumvar.latifolium was conducted, and the two varieties of C.vestitum differed slightly. The difference between the new variety and the original species is that the new variety is less branched and has orbicular and ovoid leaves that are 4–7 cm long and 3–5 cm wide, and the diameter of its capitula is larger, reaching 4.5–5.0 cm (Table 1). The morphology of C.vestitumvar.latifolium is distinct from other species in the same clade in terms of the leaf shape and length of capitula (Shih et al. 2011; Ma et al. 2020) (Table 1).

Based on a phylogenetic study of whole chloroplast genomes (Ma et al. 2020), two distinct clades were recognized in the genus Chrysanthemum. Clade I comprised C.chanetii, C.indicum, C.lavandulifolium, C.nankingense, C.zawadskii, C.dichrum, C.mongolicum, C.oreastrum, C.glabriusculum, C.boreale, and C.vestitumvar.latifolium from Tianzhu Mountain in the Dabieshan Mountain area (the Chrysanthemumzawadskii group). Clade II consisted of C.rhombifolium, C.indicumvar.aromaticum, C.potentilloides, C.hypargyrum, C.argyrophyllum, and C.vestitumvar.vestitum (Fig. 3 A, C) (the Chrysanthemumindicum group). Based on the nuclear LFAFY gene, Chrysanthemumvestitumvar.latifolium and C.vestitumvar.vestitum were treated as two distinct species in different clades (Ma et al. 2020). Accordingly, based on the morphology and molecular results, we propose that the variety Chrysanthemumvestitumvar.latifolium should be raised to the species level.

Figure 3.

The images of Chrysanthemumvestitum and ChrysanthemumdabieshanenseA, B plants growing in natural habitat C, D adaxial side of leaf (A, CChrysanthemumvestitum, voucher Z.X. Fu 610, PE, Lushi county, Henan province, China, Photographs by Zhixi Fu). (B, DChrysanthemumdabieshanense, voucher X.X.Zhu 089 CSH, Yingshan county, Hubei province, China. Photographs by Xinxin Zhu).

Taxonomic treatment

. Chrysanthemum dabieshanense

Z.X.Fu, A.G.Zhen, & Y.P.Ma nom. nov.

0332E47C-C741-58DD-BC5D-FA65340C0963

urn:lsid:ipni.org:names:77302160-1

• ≡ Chrysanthemumvestitumvar.latifolium J.Zhou & J.Y.Chen, Bull. Bot. Res. Harbin. 30: 649. 2010.

Note.

According to International Code of Nomenclature for algae, fungi, and plants (ICN) Articles 6.9, 6.11, 41.2, and 58.1 (Turland et al. 2018), Chrysanthemumdabieshanense Z.X.Fu, A.G.Zhen, & Y.P.Ma, nom. nov. is proposed here as an explicit substitute for the legitimate name Chrysanthemumvestitumvar.latifolium, because the epithet latifolium cannot be used for the present combination because of the existence of the name Chrysanthemumlatifolium (DC.) Baksay, Ann. Hist. Nat. Mus. Natl. Hung. 8: 161, 1957 (online resource from https://www.tropicos.org/name/50268974). The specific epithet “dabieshanense” refers to the name of the Dabieshan (= Ta-pieh) mountain area, located at the border of the Anhui, Hubei, and Henan Provinces, where the species occurs. Chrysanthemumdabieshanense is endemic and restricted to the Dabieshan Mountain area (Hubei and Anhui provinces). Therefore, we accept Chrysanthemumdabieshanense as a replacement name for Chrysanthemumvestitumvar.latifolium. A taxonomic treatment is presented.

Type.

China. Anhui Prov. Yuexi County, Baojia River, shady slope at the top of the hill, alt. 1500 m, 24 Sep 1953, East China Station Inst. Bot. 6935 (holotype, PE 00544099!, isotype NAS 00486826 photo seen) (Fig. 1B)

Description.

Perennial rhizomatous herbs, 60–100 cm tall. Stems sprawling, not much branched. Lower stem leaves withered at anthesis. Middle stem leaf blades orbicular or ovate-orbicular, 4–7 cm × 3–5 cm, grayish-green adaxially, grayish-white abaxially, margin above middle obtusely repand-dentate, distal stem leaves sessile or subsessile, capitula 3–10, 4.5–5 cm in diameter. Involucres cup-shaped; phyllaries in 4 rows, abaxially densely pubescent, scarious margin brown, outer phyllaries triangular or triangular-ovate, 3.5–4.5 mm, middle phyllaries lanceolate-ovate, ca. 6.5 mm, inner phyllaries obovate or oblanceolate-elliptic, 6–7 mm long. Ray floret lamina white, 1.2–2 cm long. Achenes ca. 1.5 mm long (Fig. 2, Fig. 3 B, D).

Specimens examined.

China – Anhui Prov. Jinzhai County, [without exact locality], M.B. Deng & H.T. Wei 81350, 81196 (NAS); ibidem, B. Chen CB07550 (CSH), Qianshan City, S. J. Yang et al. 7193 (NAS), Y.P. Ma MYP-20160826 (WUK); Hubei Prov. Yingshan County, Wujiashan Forest Farm, X.X. Zhu 089 (KUN, CSH); Luotian County, Tiantangzai, A.G. Zhen DBSYS708 (HIB); X.X. Zhu 211858 (KUN).

Distribution and habitat.

Endemic to the Dabieshan mountain area (Anhui and Hubei Provinces, China, Fig. 4). It grows on shaded slopes, hills, and streamsides, at alt. 800–1600 m.

Figure 4.

Distribution map of Chrysanthemumdabieshanense (black circles) in Anhui and Hubei provinces, China, based on the voucher specimen information.

Phenology.

Flowering and fruiting are observed in October.

Chinese name.

Da-Bie-Shan-Ju (大别山菊).

Citation

Fu Z, Liu X, Zhen A, Zhu X, Konowalik K, Ma Y, Li P (2022) Chrysanthemum dabieshanense, a new name for Chrysanthemum vestitum var. latifolium (Asteraceae, Anthemideae). PhytoKeys 202: 45–52. https://doi.org/10.3897/phytokeys.202.80554