Sedum yangjifengensis B. Chen & Z.W. Zhu, 2023

Zhu, Zong-Wei, Le, Xin-Gui, Li, Lu-Fei, Chen, Shi-Pin & Chen, Bin, 2023, Sedum yangjifengensis (Crassulaceae), a new species from Jiangxi, China, Phytotaxa 607 (1), pp. 105-113 : 109-111

Sedum yangjifengensis B. Chen & Z.W. Zhu sp. nov., Figs. 1 , 2 , 3 , 4 , 5 .

Type: — CHINA. Jiangxi: Guixi City, Huangsha Town , Donggang , on stonewall, elev. 450m, 7 July 2022, Zhu Zongwei, XL00466 (holotype CSH!); Shanghai City : Songjiang District , collected from cultivated individual, elevation ca. 20m, 15 June 2022, Chen Bin CB05718 (paratype CSH!) .

Diagnosis:— Sedum yangjifengensis resembles S. makinoi Maximowicz (1888: 487) during the vegetative growth period by having opposite leaves, but has slender, tufted stolons, and during the reproductive growth period, has very long internodes below the inflorescence and much greater variation on leaf size, in which the bract leaves of inflorescence are the largest ones. In reproductive period, it is similar to S. concarpum FrÖd (1935: 122) and S. lipingense by having long internodes, but has stolons, connate follicles only at 1mm and no rosette leaves present.

Description:— Biennial or perennial fleshy herb, glabrous throughout the entire plant. Roots fibrous. Sterile stems creeping, clustered, 0.5–1 mm in diam., 5–30 mm long, internodes up to 10 mm long when shaded. Flowering stems grow out from the top or leaf axils of vegetative stems, seldomly branched at the base, erect, 7 cm to 15 cm high, 1–3 mm in diam., internodes 1–4 cm long. Leaves many pairs on vegetative stems, opposite; petioles 2–3 mm long; leaf blades 5–8 mm wide, suborbiculate or spatulate, margin entire, base rounded, rarely truncate, apex rounded. Leaves 1–3 pairs on flowering stems, opposite or seldomly alternative on upper part, 2–4 clustered on the top of the branches form into bract leaves of the florescence; leaf blades turn larger form the base to the top of the branches, 5–12mm wide, 10–20mm long, elliptic or obovate, entire, apically rounded and sinuate, base attenuate into shot petiole with short broad spur. Cyme 3–5—branched, corymbiform, 3–6 cm diam., few flowered. Flower bracts similar with the inflorescence ones but gradually turn smaller. Flowers sessile, mostly 5- sometimes 4- or 6-merous; sepals uneven in size from 1 mm to 2 mm wide and 2mm to 4mm long, with a rod or spoon shape, rounded and thick on the top; petals yellow, lanceolate, 5–6 mm long, 1.5mm wide at the middle, acuminate to apex, abaxially raised into ridge and apically 0.5 mm protruding into a horn shape; stamens in two whorls, with the antepetalous stamens inserted about 1 mm from the petal base. The nectar scales inverted trapezoid, about 0.5 mm long, 0.5mm wide. Carpels narrowly ellipsoid, ca. 5 mm, base connate ca 1 mm; styles 1.5–2 mm. Follicles stellately divergent, many seeded. Seeds narrowly ovoid, about 0.8 mm long, brown papilliferous.

Distribution and Habitat: —This species is exclusively found in the valley environment and rock walls of a few adjacent valleys in Donggang, Huangsha Township, Guixi City in eastern Jiangxi Province, China (as depicted in Figure 5 ), elevation ca. 400– 800m. The surrounding vegetation includes species such as Pilea cavaleriei Léveillé (1912: 65) , Selaginella heterostachys Baker (1885: 177) , Oreocnide frutescens Tunberg (1867: 131) , Saxifraga stolonifera Meerburgh (1777: 23) and other mossy plants that thrive in damp environments.

Phenology: —Flowering from June to July; fruiting from June to August.

Etymology: —The specific epithet is derived from the type locality of Yangjifeng National Nature Reserve, Guixi City, Jiangxi Province, China.

Vernacular name:— Yáng Jì Fēng Jǐng Tiān (OiỮĄợƾ).

Conservation status: —The populations of Sedum yangjifengensis at the type locality comprises ca. 1000 individuals in several valleys nearby. More information of its distribution and number of individuals needs to be obtained for accurate assessment. According to the IUCN Red List Categories and Criteria ( IUCN 2012), the new species should be considered as Data Deficient (DD).

Other specimens examined:— Sedum makinoi : JAPAN. Nagasaki, Maximowicz, C. J . 2540 (holotype: K000732544 ); Limu City, Miyoshi Furuse 54759 ( PE01135677 , PE01135687 ); Ganshan County, Miyoshi Furuse 53825 ( PE01135681 , PE01135672 ) . CHINA. Yunnan Province, Yan L. C. C090201 ( HITBC0030803 ); Hubei Province, Li S. L . GanQL1296 ( KUN1458009 ), Li H. J . 947 ( PE00885968 ); Sichuan Province, Zhang X. S ., Ren Y . X. 4695 ( PE00914017 , PE00914018 ); Zhejiang Province, Ding B. Y ., 171 ( ZMNH0009599 ); Jiangxi Province, Liao Y. Q., TCM2471 ( JJF00043455 ). S. concarpum : CHINA. Yunnan Province, Rock, J. F . 5434 (holotype: A00042584 ; isotype: US 00100686; syntype: K000838649 , K000838650 ) , Qin R. C . 23964 ( PE00885797 , PE00885798 , PE00885799 , PE00885802 , PE00885803 , PE00885804 ), Qin R. C . 30991 ( PE00885805 , PE00885801 ), Yu D. J . 15525 ( PE00885800 ), ZHU X.X. et al.ZXX191298 ( KUN1485246 ); Hubei Province, Wang Y. M . 4985 ( PE01802440 ), Li H. J . 6688 ( PE00885790 ), Liu K. R . 0185 ( PE00885789 ); Jiangxi Province, Jian C. P . et al. 401357 ( PE 01269246 ) .

Figures

FIGURE 1. Habit and habitat of Sedum yangjifengensis. A. Habitat. B. A flowering individual with a single flower stem on barren stonewall habitat. C. A flowering individual with many flower stems in slightly fertile habit. D. Part of flowering plant, showing fruit.

FIGURE 2. Vegetative growth of Sedum yangjifengensis. A, B. Sterile stem in shaded habitat. C. Sterile stem in full sunlight habitat.

FIGURE 3. Full growth cycle of a transplanted individual. A. Collected the individual in wild, 8th June, 2021. B–I. Transplanted to Shanghai City, the dates were 26th June, 19th August, 22nd September, 7th November, 11th December of 2021 and 11th March, 2nd April, 15th June of 2022.

FIGURE 4. Morphology of Sedum yangjifengensis. A. The bottom view a cultivated individual. B. Flower stems. C. Side view of a cyme. D. Overlook of a cyme. E. Bract leaves from a cyme. F. Flowers, showing the sepals and petals. G. Flower, showing the nectar scales, carpels and follicles etc.

FIGURE 5. Distribution map of Sedum yangjifengensis sp. nov. (●) and transplant location (▲).