Euphorbia zhongiana Z. H. Chen, J. P. Li & J. B. Pu, 2024

Euphorbia zhongiana Z. H. Chen, J. P. Li & J. B. Pu , sp. nov. ( Figs. 2 View FIGURE 2 , 3 View FIGURE 3 & 4 View FIGURE 4 )

Type: — CHINA. Zhejiang Province: Yongkang City, Shizhu Town, Machedian Village , grasses on shady steep cliff of purple glutenite near hill top, 28˚50.189ʹ N, 120˚6.942ʹ E, elevation 256 m, 20 April 2023, Jun-Ping Li, Liang-Dong Xu & Zheng-Hai Chen YK 23042008 (holotype: ZM!; isotypes: ZM!, Zhejiang Academy of Traditional Chinese Medicine !) .

Diagnosis: This new species is similar to E. fauriei , but differs in its winter green habits, whole plant glabrous, cauline leaves spatulate to oblanceolate, primary involucre leaves ovate to broadly ovate, cyathophylls 2, broadly ovate, yellow-green, involucre 2.5–3.0 × 2.5–3.0 mm, ovary usually smooth, rarely sparsely microtuberous, styles connate at middle towards base, apex slightly 2–lobed, capsules smooth without tuberculate or conical verrucae, rarely sparsely and inconspicuously rugose, seed coat with reticulate wrinkle ( Table 3).

Description: Winter-green perennial herbs, glabrous. Rootstock cylindrical, light brown, fleshy, branched or not, 1–8(–20) cm long, 1–3(–5) cm thick, white in section. Stems clustered, in groups of 3–22 or more, erect, usually purple-red in the middle and lower part when young and flowering, 10–40 cm tall, 1.5–2.5 mm thick, unbranched or with weak branches in lower half. Leaves alternate, rarely pseudoverticillate on upper part of stem; stipules absent; basal cauline leaves scale-like, sparse, adnate to the stem, easily falling off, obcordate, 2–5 × 2–4 mm, purple-red abaxially, apex emarginate, sessile, gradually larger upward; middle and lower cauline leaves spatulate, 0.6–4.0 × 0.4– 0.8 cm, dark green adaxially, often purple abaxially, apex emarginate with the very apex mucronulate, or obtuse, base cuneate, margin serrated or entire, sessile; upper cauline leaves oblanceolate, 2.2–4.1 × 0.7–1.4 cm, slightly glaucous or purple-red abaxially, apex obtuse, lateral veins 6–8 pairs, margin serrate or entire, sessile. Inflorescence (cyathia) arranged in a terminal pseudumbel, sometimes also with slender, long-pedunculate dichasial cymes from subterminal axils; cymes 2–4(–5)-forked; primary rays usually 5, rarely 4 or 6, 2.5–4.0 cm long, primary involucre leaves 5(–6), ovate to broadly ovate, 1.8–3.0 cm × 1.1–1.6 cm, apex obtuse or retuse, base cuneate, entire, sessile; 2nd or 3rd(4th) order rays (1–)2, 5–25 mm long, elongated in fruit, cyathophylls 2, yellow-green, broadly ovate, 0.8–1.4 × 0.8–1.5 cm, apex obtuse or retuse, base truncate, margin entire; ultimate ray 1, 1–5 mm long, sometimes absent, cyathophylls 2, yellow-green, broadly ovate, 6–7 × 8–9 mm, entire; Cyathium bisexual, glands 4, peduncle short or subsessile, but basal-central cyathium of primary rays usually male, glands 5(–6), peduncle ca. 1 mm long; involucre campanulate, 2.5–3.0 × 2.5–3.0 mm, lobes 4 or 5, broadly triangular, apex erose; glands reniform–rounded, concave, light yellow or light orange; male flowers many, usually exserted from involucre; female flower 1, pedicel ca. 3 mm long, exserted from involucre, ovary usually smooth, sparsely microtuberous, styles 3, ca. 3 mm long, connate to below middle, apex slightly 2–lobed. Capsules nearly globose, ca. 5.0–5.8 × 5–6 mm, smooth, without tubercles, styles persistent. Seeds subglobose, ca. 2.5–2.8 × 2.5 mm, dark brown, reticulate, wrinkled, with 1 striation adaxially; caruncle light yellow, subpeltate, short stipitate.

Additional specimen examined (paratypes):— CHINA. Zhejiang Province: Jinhua City, Wucheng District, An’di Town, Shanggankou Village, under deciduous shrubs on steep slope cliff of purple glutenite beside road in valley, 28˚57.884ʹ N, 119˚36.818ʹ E, elevation 127 m, 21 February 2023, Jian-Sheng Wang, Zheng-Hai Chen & Jian-Bo Chen, WC23022101 (HHBG, ZM), WC23022102 (ZM). Wuyi County, Liucheng Town, Huatang Village, in Selaginella and mosses communities on steep wall of shady slope of purple glutenite on margin of Phyllostachys pubescens forest, elevation 226 m, 28˚39.623ʹ N, 119˚37.651ʹ E, 24 November 2022, Zheng-Hai Chen, Gen-You Li & Yi-Rong Zhu WY22112401 (ZM); ibidem, elevation 130 m, 19 April 2023, Jian-Ping Zhong, Jun-Feng Wang, Yi-Rong Zhu et al. WY23041901 (ZM); ibidem, elevation 129 m, 19 April 2023, Jian-Ping Zhong, Zheng-Hai Chen et al. WY23041903 (ZM); Wangzhai Town, Liuxiulong, in grasses on shady steep cliff of purple glutenite, 28˚48.575ʹ N, 119˚39.328ʹ E, elevation 220 m, 19 April 2023, Jian-Ping Zhong, Jun-Feng Wang, Zheng-Hai Chen et al. WY23041904 (ZM); Jiaodao Town, Shenjia Village, Fangkeng Reservoir, in grass beside hiking trail on slope, 29˚2.629ʹ N, 119˚53.444ʹ E, elevation 255 m, 9 May 2023, Jian-Ping Zhong, Jun-Ping Li & Yi-Rong Zhu WY23050904 (ZM). Yongkang County, Shizhu Town, Hongfu Temple, Daoshiyan, in grasses on shady steep cliff of purple glutenite near hill top, 28˚52.434ʹ N, 120˚8.026ʹ E, elevation 280 m, 21 February 2023, Jun-Ping Li & Zheng-Hai Chen YK23022101 (ZJFC, ZM); ibidem, in grasses on shady steep cliff of purple glutenite on hill top, elevation 300 m, 14 March 2023, Jun-Ping Li, Liang-Dong Xu & Zheng-Hai Chen YK23031401 (ZM); Qianlang Village, in grasses on shady steep cliff of purple glutenite near hill top, 28˚50.187ʹ N, 120˚6.960ʹ E, elevation 248 m, 21 February 2023, Jun-Ping Li & Zheng-Hai Chen YK23022102 (HHBG, ZM); ibidem, 20 April 2023, Jun-Ping Li, Liang-Dong Xu &Zheng-Hai Chen YK23042007 (ZM); Machedian Village, under bushes on sunny steep cliff of purple glutenite near hill top, 28˚50.189ʹ N, 120˚6.942ʹ E, elevation 256 m, 21 February 2023, Jun-Ping Li & Zheng-Hai Chen YK23022103 (ZJFC, ZM); Zhiying Town, Xianling Village, in shady grasses on steep cliff of purple glutenite in valley, 28˚54.608ʹ N, 120˚8.584ʹ E, elevation 200 m, 21 February 2023, Jun-Ping Li & Zheng-Hai Chen YK23022104 (HHBG, ZM); Fangyan Town, Fangyan Scenic Area, Shiguliao Scenic Spot, in grasses on sunny steep cliff of purple glutenite, 28˚54.940ʹ N, 120˚11.014ʹ E, elevation 280 m, 22 February 2023, Jun-Ping Li, Liang-Dong Xu & Zheng-Hai Chen YK23022201 (HHBG, ZM); Zhoushan Town, Huaihua Village, elevation 288 m, under forest on steep cliff of purple glutenite in valley, 28˚52.757ʹ N, 120˚13.016ʹ E, elevation 288 m, 20 April 2023, Liang-Dong Xu, Jun-Ping Li & Zheng-Hai Chen YK23042009 (ZM); Gushan Town, Houtanglong Second Village, Hengyanshan, in grasses on sunny steep cliff of purple glutenite, 29˚0.05ʹ N, 120˚9.367ʹ E, elevation 178 m, 3 May 2023, Jun-Ping Li YK23050301 (ZM). Lishui City, Liandu District, Laozhu Town, Daowei, in grasses on shady steep slope cliff at hill foot, 28˚28.133ʹ N, 119˚44.438ʹ E, elevation 80 m, 23 February 2023, Jian-Ping Zhong, Jun-Feng Wang & Zheng-Hai Chen LD23022301 (HHBG, ZM); Dongxiyan Scenic Spot, Dongyan, in grasses on shady steep cliff of purple glutenite, 28˚31.161ʹ N, 119˚43.113ʹ E, elevation 250 m, 23 February 2023, Jian-Ping Zhong, Jun-Feng Wang & Zheng-Hai Chen LD23022302 (ZJFC, ZM); Taiping Township, Shanyan Temple, in grasses on sunny steep cliff of purple glutenite in valley, 28˚34.853ʹ N, 119˚46.763ʹ E, elevation 275 m, 19 April 2023, Jian-Ping Zhong, Jun-Feng Wang & Zheng-Hai Chen LD23041907 (ZM). Quzhou City, Kecheng District, Shishi, Lankeshan Scenic Spot, Meiyanding, in wet grass at mountain top, 28˚52.450ʹ N, 118˚54.938ʹ E, elevation 167 m, 7 March 2023, Hua-Min Zhu, Mei-Fang Wang & Zheng-Hai Chen KC23030701 (ZM); ibidem, in grasses on sunny cliff of purple glutenite at hill foot, 28˚52.429ʹ N, 118˚54.741ʹ E, elevation 130 m, 7 March 2023, Hua-Min Zhu, Mei-Fang Wang & Zheng-Hai Chen KC23030702 (ZM).

Distribution:— Euphorbia zhongiana is currently found only in Wucheng District, Yongkang County, Wuyi County in Jinhua City, Liandu District in Lishui City, and Kecheng District in Quzhou City, all Zhejiang Province, Eastern China ( Fig. 5 View FIGURE 5 ).

Habitat:— Euphorbia zhongiana is usually found only on the steep slopes or cliffs of Danxia landform hills, often grows under deciduous broad-leaved forests, forest edges, under deciduous shrubs, in damp communities of Selaginella and moss, in grass communities, and in grass of rocky pit on cliffs. The soil is purple sandy soil formed by the weathering of purple sandy conglomerate, with an elevation from 80 to 300 m above sea level.

Phenology:—Flowering usually from early February to mid-March, fruiting from April to May.

Etymology:—The species epithet ‘ zhongiana ’ honours Mr. Jian-Ping Zhong, who first found, collected, cultivated and observed this new species and has made significant contributions to the floristic knowledge of Zhejiang Province. The Chinese name of Euphorbia zhongiana is proposed here as 丹º大ª refering to its main distribution area in Danxia landform of Zhejiang.

Conservation assessment:—Although 15 populations of Euphorbia zhongiana have been found, they are scattered in 3 cities, 5 counties and 12 towns, and their habitats are severely fragmented. Each community covers a very small area, with the exception of Wucheng, which has a populated area of 300 m 2; all other communities have an area of only 10–50 m 2. It is a custom that the roots were used for medicinal purposes in the Liandu District. If a formal assessment were performed, we suggest Euphorbia zhongiana that should be considered as vulnerable (VU) based on IUCN Red List ( IUCN 2022).

Notes:—The fleshy root of this species is highly toxic. It is commonly known as "五êaeẑ"["Five Golden Flowers", means it has five yellow primary involucral leaves], "坛壁伤ñ" ["Rock Wall Injury Medicine", means that its root is used in folk medicine to treat traumatic injuries], "kflff" ["Barley Ripens to Death", means that when barley is ripe, it also withers away, indicating the time when it enters the dormancy period] in Liandu District, Lishui City. It is used as folk medicine to treat traumatic injuries.