Thalictrum austrotibeticum J. Y. Li, L. Xie & L. Q. Li, 2015

Li, Jin-Yu, Xie, Lei & Li, Liang-Qian, 2015, A new species of Thalictrum (Ranunculaceae) from southern Tibet (Xizang), China, Phytotaxa 207 (3), pp. 281-285 : 281-284

Thalictrum austrotibeticum J. Y. Li, L. Xie & L. Q. Li , sp. nov. ( Figs. 1–2 ).

Similar to Thalictrum finetii Boivin (1945: 113) by its floral structure such as filiform filaments, mucronate anthers, hairy pistils, not winged stigma, and compressed achenes with a dorsal margin, but distinguished by its much larger and bluish leaflets (usually 4–5 cm long in Th. austrotibeticum vs. less than 2 cm long in Th. finetii ), pubescent pedicels (glabrous in Th. finetii ), purple filaments (white in Th. finetii ), and white or pink sepals (yellowish green in Th. finetii ). Thalictrum finetii is distributed in eastern Xizang and Hengduan Mountains and the new species is distributed in southern Xizang.

Type:— CHINA. Xizang: Nyalam, around 707 Bridge , 28°4’58”N, 85°59’56”E, 28 July 2013, PE-Tibetan Expedition 4387 (holotype PE!, barcode: PE2427713; isotypes PE!)

Description:—Herbs perennial, plants 1.2–2 m tall. Stems glabrous, simple or branched. Basal leaves withered at anthesis. Primordial leaves bluish-green. Distal cauline leaf often narrow, margin often irregularly lobed; leaf blade often 3-pinnate,large, ca. 40–60 cm long; petiole 2–7.5 cm, distinctly sheathed, leaf indistinctly 3-lobed; leaflet blade round to obovate, broadly ovate, or orbicular, large,2.5–5.5 (–7) ×2.5–5.7 (7.5) cm, papery, base rounded to cordate, apex shortly acute; margin coarsely toothed; veins adaxially flat, abaxially raised, pubescent. Inflorescence cymose paniculate, many-flowered. Pedicel slender, 0.4–1.8 cm, pubescent. Flowers bisexual. Sepals often 4, deciduous, white or pink, elliptic-ovate, about 3–5 mm long.Stamens 4–9 mm; filament purple, filiform; anthers narrowly oblong, mucronate, 1.5–2.5 mm, apex mucronate. Carpels 7–14; style equal or slightly longer than ovary, erect, stigma not winged, ca. 1.0– 1.5mm, ovary covered with very short hairs. Achenes subsessile, compressed; stipe ca. 0.5 mm; body hemispheric or hemiobovoid, ca. 5–6 mm long.

Distribution:—This species has been found in the valleys of Gyrong, Yadong, and Nyalam counties along central Himalayas, and common in distribution areas. The species probably also occurs in adjacent areas of India, Nepal, and Bhutan.

Habitat:—This species occurs in forest margins and grassy slopes with an altitudinal range of 2300–3900 m.

Phenology:—Flowering early July to August, Fruiting from late July.

Etymology:—The specific epithet is the combination of “austro-”= south, and “tibeticum”= Xizang, referring to its distribution area.

Additional specimens examined (paratypes):— CHINA. Xizang: Gyirong, near Zha cun, 28°23’57”N, 85°21’32”E, 23 July 2013, PE-Tibetan Expedition 4130 (PE) ; Gyirong , 14 July 2011, L. He, Y. Q. Ruan & C. Shang 110714-14 (BJFC) ; Nyalam, Lixin cun, 27°58’34”N, 85°58’34”E, 27 July 2013, PE-Tibetan Expedition 4289 (PE) ; Yadong, north-west of the Yadong city, 93–95 th km of 714 Rd. , 27°33’51”N, 88°55’16”E, 7 July 2013, PETibetan Expedition 2848 (PE) .

Figures

FIGURE 1. Thalictrum austrotibeticum J. Y. Li, L. Xie & L. Q. Li. a. Mature cauline leaf. b. Inflorescence. c. Pistil. d. Stamen. e. Sepal. f. Fruit. (Drawn based on an isotype of PE-Tibetan Expedition 4387 by G. Q. Zhao).

FIGURE 2. Thalictrum austrotibeticum J. Y. Li, L. Xie & L. Q. Li. a.A blooming individual. b & e. Upper and lower leaves showing color and morphology variation. c. Inflorescence. d. Mature flower and fruits showing purple filaments and compressed fruits. (Photos from Gyirong and Nyalam populations by J. Y. Li, L. Xie, and X. T. Ma)