WANG Wen-Tsai

(State Key Laboratory of Systematic and Evolutionary Botany,Institute of Botany,Chinese Academy of Sciences,Beijing 100093)

Abstract A species of the genus Thalictrum(Ranunculaceae), T.nepalense, is described as new from eastern Nepal. It is closely related to T.saniculiforme DC., differing from the latter in its taller 3-leaved and 3-branched stem, compound monochasia with only ultimate branches divaricate, albove clavate and below filiform stamen filaments, and anthers not apiculate at apex.

Key words Ranunculaceae;Thalictrum;new species;Nepal

Fig.1 T.nepalense A. Roots and basal part of stem; B. Upper part of flowering plant; C. Stamen; D. Carpel; E. Achene(from holotype)

1 大關(guān)唐松草 圖1

ThalictrumnepalenseW. T. Wang, sp. nov. Fig.1.

(Subgen.ThalictrumSect.LeptostigmaBoivin)

Ob plantas totas glabras, folia 3-ternata, florem carpella numerosa stylis longis apice unciformibus vel circinatis et stigmatibus inconspicuis praedita ferentem species nova haec est arcte affinisT.saniculiformiDC., a quo caule altiore 3-foliato et 3-ramoso, monochasiis compositis ter ramosis, tantum eorum ramis ultimis divaricatis, staminum filamentis superne clavatis inferne filiformibus, antheris apice obtusis haud apiculatis differt. InT.saniculiformi, caulis humilior, 1-foliatus et 1-ramosus vel nudus, monochasia composita semel vel bis divaricata, staminum filamenta anguste linearia, et antherae apice apiculatae sunt.

Perennial herb, totally glabrous. Stem ca. 35 cm tall, above base 2 mm across, 3-leaved and 3-branched, with branches 1-leaved. Basal leaves not seen. Cauline leaves 3-ternate, slightly long or shortly petiolate or sessile; blades 5-8×6-8 cm; leaflets papery, obovate, broadly ovate, broadly rhombic or subpentagonal, 0.6-1.7×0.4-1.9 cm, at apex rounded, at base broadly cuneate, subcordate or subtruncate, 3-dentate or 3-lobed, with lobes entire or 1-2-dentate, 3-5-nerved, nerves adaxially slightly prominent or subflat, abaxially prominent, with nervules forming conspicous nervous nets; petiolules filiform, 0.5-8 mm long; petioles 0-5.5 cm long, at base narrowly vaginate. Compound monochasia terminal, including peduncules 5-13 cm long, thrice branched and only ultimate branches more or less divaricate; peduncles 3-6.8 cm long; most bracts foliaceous, or ternate, uppermost ones small, simple, elliptic or obovate, and entire; pedicels 2-5.5 mm long. Flower: Sepals caducous, not seen. Stamens ca. 14; filaments 2.5-3 mm long, above clavate, as broad as anthers, below filiform; anthers yellowish, narrow-oblong, ca. 0.8 mm×0.2 mm, at apex obtuse. Carpels 9-12, sessile; ovaries ca. 1.2 mm×0.5 mm; styles 0.8-1.2 mm long, at apex hooked or circinate; stigmas inconspicuous. Achenes sessile, compressed, narrowly elliptic, 2.2-3 mm×0.25-0.4 mm, on each side longitudinally and thinly 3-ribbed; persistent styles 0.8-1.2 mm long, at apex hooked.

E.Nepal: Sagarmatha Zone, Solukhumbu Distr., Sete(2 500 m). Lamjura La(3 500 m). Taktor(2 850 m)[86°26′-31′E, 27°24′N] 30 July 1997. Coll. M. Wakabayashi, M. Amano, M. Mori, K. R. Rajbhandari & K. Shinozaki No. 9720035(holoytpe, PE).

In having totally glabrous plants, 3-ternate leaves, flower bearing numerous carpels with long styles hooked or circinate at apex and inconspicuous stigmas this new species is closely related toT.saniculiformeDC. also with the characters just stated above, and from the latter differs in its taller 3-leaved and 3-branched stem, thrice branched compound monochasia with only ultimate branches divaricate, above clavate and below filiform filaments of stamens, and not apiculate anthers. InT.saniculiforme, the stems are lower, only 1-leaved and 1-branched, or naked, the compound monochasia are once or twice divaricate, the stamen filaments are narrowly linear, and the anthers are apiculate at apex[1-3].

Acknowledgements The author is grateful to Mr. Sun Ying-Bao for making the drawing.