Chrysanthemum yantaiense M. Sun et J. T. Chen, 2018

Chen, Jun-Tong, Zhong, Jian, Shi, Xue-Jun, Zhang, Qi-Xiang & Sun, Ming, 2018, Chrysanthemum yantaiense, a rare new species of Asteraceae from China, Phytotaxa 374 (1), pp. 92-96 : 92-95

Chrysanthemum yantaiense M. Sun et J. T. Chen , sp. nov. ( Figs. 1 , 2 , 3 )

This species is most similar to Chrysanthemum indicum Linnaeus (1753: 889) , but its characters are very different in four features: most species of Chrysanthemum are erect, but its stem is prostrate, with a height of less than 20 cm, and a large crown; the synflorescence types are different: single capitula are terminal on the lateral branchlets, or there are 2 to 4 capitula from the uppermost leaf axils of the lateral branchlets, the flowering branches forming a large lax paniculate synflorescence; the capitula are obviously larger, 2.5–3.0(–3.5) cm in diameter; there is a clear difference in leaf morphology: leaves thicker, nearly leathery, veins prominent on both surfaces. Chrysanthemum lavandulifolium (Fisch. ex Trautvetter 1870: 181) Makino (1909: 20) and C. nankingense Handel-Mazzetti (1938: 258) are close to C. indicum , so we also examined the specimens of these two species, and there are obvious differences in the characters among these four species. Morphological comparisons with similar species are shown in Table 1.

Type: CHINA. Shandong: Yantai City , 37°29 ′ 2 ″ N, 121°38 ′ 53 ″ E, 5 m, 7 August 2012, M. Sun 120807 (holotype: BJFC; isotypes: PE) .

The main morphological characters of the new species: Perennial herb, 10~ 20 cm high, over 2 m wide. Stems and branches prostrate, all stems when young covered with densely and thickly appressed grayish white T-shaped hairs, old stems nearly glabrescent. Lateral branches nearly flat, the main stem branching at 5–8 cm from the base, branches dense, internodes ca. 1.2–1.5 cm, crown width 1.2 × 1.9 m (1 year old in the autumn), over 2.0 × 2.0 m (two years). Leaves nearly leathery, veins prominent on both surfaces; leaves when young with densely villous T-shaped hairs, adaxially dark green, old leaves glabrescent, only the main veins with sparsely appressed T-shaped hairs; abaxially gray-green, densely white appressed T-shaped hairs. The stem leaves withering over time, most lower leaves withered at anthesis. Stem leaves: petiole ca. 1–1.5 cm, with narrow wings, 2 stipule-shaped lobes, 3–5 × 5–7 mm, deeply bilobate, leaf blade broadly ovate, 4.0–6.0 × 3.4–4.5 cm, mainly pinnatifid, base gradually narrowed into petiole, cuneate to broadly cuneate, margin with hard coarse teeth, primary lateral segments 2–3 pairs; ultimate lobes ovate, every lobes ca. 3-denticulate; upper leaves of the main branch extant at anthesis, smaller in size. Lateral flowering branchlets: stems grayish-green at anthesis, ca. 5–16 cm long, leaves smaller, ovate to broadly ovate, mostly pinnatilobed, 1.5–2.0 × 0.6–1.0 cm, their two stipule-shaped lobes are distinct from the stipule-shaped lobes on the main branch, entire or occasionally lobate, smaller. The branchlets under the capitula ca. 1.5–5.0 cm, bracteal leaves 0–4, alternate, upper bracteal leaf linear, ca. 3.0–8.0 × 0.8–1.0 mm, margin entire; lower bracteal leaf narrowly ovate, 1–3-denticulate, ca. 7.0–10.0 × 1.0–5.0 mm. Synflorescence paniculate, lax and large. Capitula 2.5–3.0(–3.5) cm in diameter, mainly solitary in upper leaf axils of upper branchlets; involucre cup-shaped, 12–16 mm in diameter, with 24–30 phyllaries in 4–5 rows, margins broadly scarious, grayish brown, apex obtuse, 1.2–4.2 × 2.0– 7.2 mm. Ray floret lamina yellow, 21–29, apex entire or 1–3-denticulate, 2.8–3.8 × 11.3–16.6 mm. Disk florets many, bisexual, fertile; corolla yellow, tubular, 5-lobed. Achenes obovoid, ca. 1.0 mm long. Pappus absent. Flowering from October to November.

Distribution and habitat: —The new species is currently known from Mouping District, Yantai, Shandong, China, at elevations between 4 m and 15 m. It is locally common and grows on barren reefs and rock crevices and infertile and thin soils together with Rumex sp. ( Polygonaceae ), Gaura parviflora ( Onagraceae ), Metaplexis japonica ( Asclepiadaceae ), Iris dichotoma ( Iridaceae ), Artemisia sp. ( Asteraceae ), Hemerocallis sp. ( Liliaceae ), Vitis sp. ( Vitaceae ), etc.

Phenology: —Flowering specimens were collected in October.

Etymology: —The specific epithet refers to the distribution of the new species. The Chinese name is given as “Dz Ṉffi” because of prostrate stems and branches of the species.

Additional specimen of C. yantaiense examined (paratype): CHINA. Shandong: Yantai City, Mouping District, 20 October 2017, M. Sun & J.T. Chen 171020 (BJFC).

Specimens of C. indicum examined: — CHINA. Shandong: Laoshan , 3 October 1935, Y. C. Wang W.712 ( PE) ; Qufu City, Nanshan , 9 October 1933, K. M. Liou L.1839 ( PE) ; Liaoning: Anshan city, 27 September 1950, Q. T. Li, Y. L. Zhou & P. Y. Fu 2493 ( PE) ; Dalian City , Xinjin County, 25 September 1959, Jinxian Exped. 106 ( IBK) ; Huludao City , Xingcheng County, 21 September 1985, Q. L. Wang 286 ( IFP) ; Jinzhou City , 15 October 1962, W. Wang 3528 ( PE) ; Hebei: Qinhuangdao City, Beidaihe District seaside, 22 October 1952, C. s.n. ( PE) ; Baoding City , Fuping County, 25 September 1971, Anonymous Fu. 91 ( PE) ; Beijing: Beijing City , 1 October 1929, F. T. Wang 20355 ( PE) .

Specimens of C. lavandulifolium examined: — CHINA. Shandong: Zhoucheng City, 21 October 2012, Y. T. Hou , C. Y. Guo, L. S. Xu & C. L. Hou 12010986 ( QFNU) ; Taian City , 12 September 1959, T. Y. Zhou 7196 ( PE) ; Hebei: Xingtai City , September 1950, Y. Liu 13909 ( PE) ; Chicheng County, 8 September 1959, Anonymous 4468 ( PE) ; Xinglong County, 27 September 1951, W. C. Wang , J. Zhang & F. S. Zhang 2727 ( PE) ; Zhangjiakou City , 20 September 1959, Anonymous 4750 ( PE) ; Beijing: Beijing City , 18 September 1950, W. C. Wang 627 ( PE) ; Beijing City , 12 September 1955, C. G. Yang 1787 ( PE) ; Liaoning: Huludao City , 29 September 1958, C. S. Wang 3287 ( PE) .

Specimens of C. nankingense examined: — CHINA. Jiangsu: Wuxi City, Huishan , 12 November 1990, W. X.Wu 9019 ( NAS) ; Jiangxi: Y. G. Xiong 9093 ( IBSC) ; Nanjing City , 15 October 2006, Y. R. Lin 06-330 ( IBSC) ; Zhejiang: Linan City , 18 October 1923, K. K. Tsoong D485 ( PE) ; Linan City, 10 October 1958, Anonymous 31196 ( PE) .

Conservation status: As per currently available data, the species should be assigned to the category ‘Data Deficient’ (DD) of IUCN (2016). The precise conservation status of the population(s) has not been determined, so further explorations are needed to assess its distribution and conservation status. The type locality of this new species is an unprotected small island. The distribution of the new species is limited. Increasing human activities and habitat destruction may cause threat to the existence of this rare species.

Figures

FIGURE 1.Chrysanthemum yantaiense M.Sun & J.T.Chen.A. Plant, B–C.Two typesof leaves,D.Side viewof paniculate synflorescence, E. Top view of paniculate synflorescence, F. Capitula, G. Ray floret and disk floret, H. T-shaped hairs.

FIGURE 2. Chrysanthemum yantaiense M. Sun & J.T. Chen. A. Habit, B. Leafy branch, C. Whole plant, D. Flowering branch forming paniculate synflorescence, E. Leaf, F. Capitula, G. Involucres, H. Ray florets, I. Disk florets, J. Young leaf, K. T-shaped hairs.

FIGURE 3. Chrysanthemum yantaiense M. Sun & J.T. Chen (Cultivated). A. Whole plant, B. Flower bud period, C. Flowering period.