Abstract. Delphinium calthifolium Q. E. Yang & Y. Luo, a new species of Ranunculaceae from Beichuan County, Sichuan Province, is described and illustrated. The new species is distinguished by its undivided, orbicular-cordate or broadly ovate-cordate leaves and very narrowly subulate-cylindric spur of the upper sepal. It is perhaps related to D. delavayi Franchet by its blue staminodes, with bifid, ventrally sparsely yellowish barbate limb, and its transversely undulate seed surface architecture of minute scales.

Key words: China, Delphinium, Ranunculaceae.

In the course of examining specimens of Ranunculaceae in the herbarium of the Chengdu Institute of Biology (CDBI), Chinese Academy of Sciences, the following new species of the genus Delphinium L. was discovered.

Herba perennis; caule cum inflorescentia 25--40 cm alto, densiuscule patenterque albido-hirtello, simplice, gracili. Folium basale 1; petiolo ca. 13 cm longo basi paulo dilatato; lamina indivisa, orbiculari-cordata vel late ovato-cordata, ca. 7 cm longa, ca. 6 cm lata, utrinque glabra, margine apiculato-crenata, apice acuminata. Folium caulinum 1; petiolo 1--5 cm longo; lamina ei folii basalis simili, raro minore et triloba, utrinque glabra vel supra sparse albido-hirtella. Inflorescentia racemosa, laxa, 3- ad 6-flora, 5--12 cm longa; rhachide adpresse hirtella; bracteis lanceolatis vel subulatis, integris, dense adpresse hirtellis, 0.5--1.0 cm longis, infimis interdum trilobis et majoribus; pedicellis divaricatis, 2--5 cm longis, adpresse hirtellis, prope medium 2-bracteolatis, bracteolis lanceolatis, 0.2--0.5 cm longis, dense hirtellis. Flores subhorizontales, ca. 3 cm longi; sepalo superiore late ovato, calcari tenuissme subulato-cylindrico, ca. 2.5 cm longo basi ca. 3 mm crasso paulo recurvato, extus pubescente intus glabro, lateralibus late ellipticis, ca. 12 mm longis, ca. 7 mm latis, inferioribus ellipticis, ca. 13 mm longis, ca. 5 mm latis; petalis caeruleis, glabris, apice acutis; staminodiis caeruleis, limbo ovato bifido ca. 7 mm longo, adaxialiter sparse flavido-barbato, margine sparse ciliato, ungue ca. 5 mm longo, glabro; staminibus numerosis, glabris, filamentis integris; ovariis 2 vel 3, glabris. Folliculi seminibus ellipsoideis, transversaliter undulato-lamellato-squamulosis.

Herbs perennial. Stem simple, slender, together with inflorescence 25--40 cm tall, densely spreading white hirtellous. Basal leaf 1; petiole ca. 13 cm, base slightly dilated; leaf blade undivided, orbicular-cordate or broadly ovate-cordate, ca. 7 ´ 6 cm, glabrous, margin apiculate crenate, apex acuminate. Cauline leaf 1; petiole 1--5 cm; leaf blade similar to basal one in shape, rarely smaller and trilobate, glabrous on both surfaces or sparsely whitish hirtellous adaxially. Inflorescence racemose, lax, 5--12 cm, 3- to 6-flowered; rachis appressed hirtellous; bracts lanceolate or subulate, undivided, 0.5--1.0 cm, densely appressed hirtellous, lowermost bract sometimes trilobate and larger. Flowers subhorizontal, ca. 3 cm; pedicel divaricate, 2--5 cm, appressed hirtellous, 2-bracteolate near middle; bracteoles lanceolate, 0.2--0.5 cm, densely hirtellous. Sepals blue; upper sepal broadly ovate; spur very narrowly subulate-cylindric, slightly downcurved, ca. 2.5 cm ´ ca. 3 mm thick at base, pubescent outside, glabrous inside; lateral sepals broadly elliptic, ca. 12 ´ 7 mm; lower sepals elliptic, ca. 13 ´ 5 mm. Petals blue, glabrous, apex acute. Staminodes blue; limb ovate, bifid, ca. 7 mm, ventrally sparsely yellowish barbate, margin sparsely ciliate; claw ca. 5 mm, glabrous. Stamens numerous, glabrous; filaments entire. Ovaries 2 or 3, glabrous. Seeds ellipsoid, transversely undulate lamellar squamulose.

Habitat and distribution. Delphinium calthifolium is currently known only from the type gathering, made in forest at 2300 m in Beichuan County in northern Sichuan Province. The type locality is not easily accessible and was probably never carefully botanized before the new species was collected in 1984.

Delphinium calthifolium is a remarkable species in the genus because of its undivided and orbicular-cordate or broadly ovate-cordate leaf blades as well as the very narrowly subulate-cylindric spur of the upper sepal. Staminodes are blue with a bifid, sparsely yellowish barbate limb; seed surfaces are remarkable for their transversely undulate surface architecture of minute scales. From these features of staminodes and seeds, this species may be most closely related to D. delavayi Franchet in D. subg. Delphinastrum (DC.) Petermann sect. Elatopsis Huth ser. Pogonantha W. T. Wang. The specific epithet refers to the similarity of the undivided, cordate leaves to those of Caltha L., another genus of Ranunculaceae.

Acknowledgments. We are most grateful to Gao Xinfen, curator of the Herbarium of Chengdu Institute of Biology, Chinese Academy of Sciences, for her kind help and hospitality during our sojourn in Chengdu. Our thanks also go to Wang Wentsai in the Laboratory of Systematic and Evolutionary Botany, Institute of Botany (Beijing), Chinese Academy of Sciences, for his invaluable direction during the course of research, and to Sun Yingbao for his illustration. This work was supported by the National Natural Science Foundation of China (Grant No. 30070057).