Rhodiola yushuensis S.Y. Meng et J. Zhang, 2022

Rong, Yu-Lin, Li, Guo-Dong, Zheng, Hai-Lei, Zhang, Jun & Meng, Shi-Yong, 2022, Rhodiola yushuensis, a new species of Rhodiola (Crassulaceae) from Qinghai, China, Phytotaxa 548 (1), pp. 63-72 : 69-71

Rhodiola yushuensis S.Y. Meng et J. Zhang sp. nov. ( Figs 5 , 6 )

Type:— China. Qinghai, Yushu, Sanjiangyuan , N33° 1’ 34.20” E97°12’ 54.48”, 3,478 m, 28 June 2020, J . Zhang , C046 (holotype: PEY! Isotype: PEY! PE!) .

Diagnosis:—Similar to Rhodiola smithii (Hamet) S. H. Fu but differing in caudex leaves, outer caudex leaves are wide triangular while the inner caudex leaves with distinctly petiole are obovate-triangular.

Description:—A perennial low and small herb, 2-4 cm high. Caudex nearly erect, few branches, robust, typically 6-10 mm across; apical part often short, branched and accrescent, crowned by persistent old flowering stems. There are two types of caudex leaves. Outer caudex leaves scalelike, wide triangle, yellow to maroon, long 1.8-2 mm, wide 2.5-3.0 mm. Inner caudex leaves leaflike, long obovate-triangular with the entire margin, acute-obtuse at the apex, 12-25 mm long, 3-8 mm wide, petiole 6-35 mm. Flowering stems 1–3 from the apex of each caudex branch, deciduous, 11–30 mm long, erect, simple, terete and smooth. Leaves alternate, few and scattered, petiole 1-3mm long, spurless, obovatetriangular, glabrous, 6-11 mm long, 2-5 mm wide, entire; Inflorescences terminal, 4-5 flower buds form cymes , flower buds are pink, pink to red when blooming. Bracts leafy. Flowers 5-merous, calyx 5, base connate 0.5 mm, long triangular, apex acuminate, entire, green, fleshy, 2.5-3 mm long, 0.8–1.0 mm wide; Petals 5, free, oblong, pink to red, apex shortly acuminate, long 6-8 mm, wide 1.5-2.0 mm; Stamens 10, slightly shorter than petals, antepetalous ones inserted ca. 0.5 mm from petal base, long 6-8 mm, antesepalous ones 6-8 mm long, anther red; Nectar scales 5, yellow, wide quadrangular, apex emarginate, ca. 0.7 mm long, ca. 0.5 mm wide; Carpel 5, erect, long oblong, long 5-7 mm, base separated; Style long ca. 2.5 mm; Follicles 6–8 mm long, each carpel erect, Styles usually out curved, 4–8 seeds each carpel. Seeds oblong-lanceolate, 0.4-1.2 mm long, 0.2-0.4 mm wide.

Phenology: Flowers from June to July; fruits from July to October.

Habitat: Rock crevices of the valley, 3800–4000m.

Etymology: The specific epithet of this new species refers to Yushu City.

Common name (assigned here): Yu Shu Hong Jing Tian (玉树ṱạƛ; Chinese name).

Proposed IUCN conservation status: The new species has been found in the rock crevices of the Tong-tian River, Zha-qu River and Zi-Qu River valley in Yushu City, Qinghai Province, China. Because there is no medicinal and economic value, the populations remain relatively stable. However, the habitats are mainly in river valleys and roadsides, and more active economic and construction activities may affect the population. The species is considered to be “Vulnerable” (VUD1) according to the IUCN Red List Criteria (IUCN 2017).

Additional specimens examined (paratypes): CHINA. Qinghai, Yushu, Sanjiangyuan, 3,890 m, 28 August 2010, S. Y . Meng & J. Q . Zhang, zhang02 ( PEY); Tongtian River , N33° 7’ 35.73” E97°7’ 55.21”, 3,536 m, 27 June 2020, J . Zhang, C037 ( PEY) .

Figures

FIGURE 5. Rhodiola yushuensis S.Y. Meng et J. Zhang, (A) natural habitat, (B) cyme, (C) fruits.

FIGURE 6. Line drawing of Rhodiola yushuensis S.Y. Meng et J. Zhang, (A) Habit; (B) Inner caudex leaves (leaflike); (C) Outer caudex leaves (scalelike); (D) Petal and Stamens; (E) Sepal; (F) Nectar scales; (G) Fruit; (H) Seed. Drawing by Ye Lv.