Recent phylogenetic analyses have revealed that Chrysanthemum vestitum var. latifolium and C. vestitum var. 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, Chrysanthemum vestitum var. 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, Chrysanthemum dabieshanense Z.X.Fu, A.G.Zhen, & Y.P.Ma, nom. nov. is proposed as the new name for Chrysanthemum vestitum var. 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.

Asteraceae, China, Chrysanthemum endemism, taxonomy

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 Chrysanthemum zawadskii group, which is distributed in northern China and has erect stems and large capitula with white or purple ray florets, and the Chrysanthemum indicum 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), Chrysanthemum vestitum var. vestitum from the Funiu Mountain in Henan Province and C. vestitum var. latifolium from the Tianzhu Mountain in Anhui Province represent two distinct clades. Morphologically, C. vestitum var. 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 Chrysanthemum vestitum var. 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 Chrysanthemum dabieshanense.

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 Chrysanthemum vestitum (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 Chrysanthemum vestitum (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. vestitum var. latifolium.

Figure 1. 

The images of the holotype of Chrysanthemum vestitum and Chrysanthemum vestitum (Hemsl.) Stapf. var. latifolium A the lectotype of Chrysanthemum vestitum (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 Chrysanthemum vestitum (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!).

The morphological characteristics of C. vestitum var. 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.

Figure 2. 

A plant of Chrysanthemum vestitum (Hemsl.) Stapf var. 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.

Zhou and Chen (2010) reported a new variety: Chrysanthemum vestitum (Hemsl.) Stapf. var. latifolium J.Zhou et J.Y.Chen from China (Fig. 1B). In their study, the holotype specimen of Chrysanthemum vestitum var. latifolium was collected from the Tianzhu Mountain (Anhui Province, Fig. 1B). The variety Chrysanthemum vestitum var. 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 Chrysanthemum vestitum (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. vestitum var. 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. vestitum var. 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. vestitum var. latifolium from Tianzhu Mountain in the Dabieshan Mountain area (the Chrysanthemum zawadskii group). Clade II consisted of C. rhombifolium, C. indicum var. aromaticum, C. potentilloides, C. hypargyrum, C. argyrophyllum, and C. vestitum var. vestitum (Fig. 3 A, C) (the Chrysanthemum indicum group). Based on the nuclear LFAFY gene, Chrysanthemum vestitum var. latifolium and C. vestitum var. 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 Chrysanthemum vestitum var. latifolium should be raised to the species level.

Figure 3. 

The images of Chrysanthemum vestitum and Chrysanthemum dabieshanense A, B plants growing in natural habitat C, D adaxial side of leaf (A, C Chrysanthemum vestitum, voucher Z.X. Fu 610, PE, Lushi county, Henan province, China, Photographs by Zhixi Fu). (B, D Chrysanthemum dabieshanense, 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.

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

≡ Chrysanthemum vestitum var. 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), Chrysanthemum dabieshanense Z.X.Fu, A.G.Zhen, & Y.P.Ma, nom. nov. is proposed here as an explicit substitute for the legitimate name Chrysanthemum vestitum var. latifolium, because the epithet latifolium cannot be used for the present combination because of the existence of the name Chrysanthemum latifolium (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. Chrysanthemum dabieshanense is endemic and restricted to the Dabieshan Mountain area (Hubei and Anhui provinces). Therefore, we accept Chrysanthemum dabieshanense as a replacement name for Chrysanthemum vestitum var. 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 Chrysanthemum dabieshanense (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).

The authors thank curators and relevant staff of the CSH, HIB, K, KUN, PE, WUK herbaria who granted access to their collections and images. We also thank Dr. Caifei Zhang (Wuhan Botanical Garden, the Chinese Academy of Sciences), Dr. Guojin Zhang (Pennsylvania State University), Dr. Shuai Liao (East China Normal University) and Dr. Peiliang Liu (Northwest University), Associate Prof. Longfei Fu (Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences) for their critical comments and great help, Mr. Xingyong Cui (Beijing Forestry University) for drawing distribution map. We also thank the anonymous reviewers and editor for constructive criticism of the original manuscript. This study was financially supported by the National Natural Science Foundation of China (No. 32000158, 31872710, 31970225), the National Science & Technology Fundamental Resources Investigation Program of China (No. 2019FY101809, 2021XJKK0702) and the Foundation of Sustainable Development Research Center of Resources and Environment of Western Sichuan, Sichuan Normal University (No. 2020CXZYHJZX03).