Blackwell Science, LtdOxford, UKBOJBotanical Journal of the Linnean Society0024-4074The Linnean Society of London, 2005? 2005 1491 115119 Original Article NEW SPECIES OF VIOLA FROM CHINA Y.-S. CHEN and Q.-E. YANG

Botanical Journal of the Linnean Society, 2005, 149, 115–119. With 5 figures

A distinctive new species of Viola (Violaceae) from Yunnan, China YOU-SHENG CHEN and QIN-ER YANG* Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, People’s Republic of China Received August 2004; accepted for publication January 2005

A new species of Viola (Violaceae) from north-western Yunnan, China, is described and illustrated. Viola dimorphophylla Y. S. Chen & Q. E. Yang sp. nov. is endemic to Zhongdian County, north-western Yunnan, and is very easily distinguishable from all other Chinese species of the genus by having obviously dimorphic leaves, with the basal ones being long petiolate, undivided and widely cordate, and the cauline ones sessile, linear and verticillate. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149, 115–119.

ADDITIONAL KEYWORDS: section Dischidium Ging. – subsection Brevicalcaratae W. Beck. – taxonomy.

INTRODUCTION In the course of preparing an account of the Violaceae for the Flora of China, the name Viola verticillata S. Y. Chen & C. Ho (Chen, 1985) drew our attention. Judging from the original description given only in Chinese and the accompanying illustration, this species is very easily distinguishable from all other Chinese species of the genus by having cauline leaves that are sessile, linear and verticillate. Unfortunately, when Chen described this species, he did not give a Latin diagnosis and did not cite any specimen. He merely gave a Chinese description and stated that the species is distributed in north-western Yunnan, China (Chen, 1985). Therefore, the publication is not valid according to the International Code of Botanical Nomenclature (Saint Louis Code) (Greuter et al., 2000). In the account of the Violaceae of the Flora Reipublicae Popularis Sinicae vol. 51 (Wang, 1991), this species was not mentioned. To make the situation more complicated, V. verticillata S. Y. Chen & C. Ho (1985) is a later homonym of V. verticillata Ortega (1797), the basionym of Hybanthus verticillatus Baillon, a plant occurring in the south-western United States and Mexico (Baillon, 1873; Britton & Brown, 1897; Melchior, 1925). Thus *Corresponding author. E-mail: [email protected]

the name V. verticillata cannot be used for the species under question even if we are to validate it by giving a Latin description and designating a type for it. In 2003, from the Herbarium of Chongqing Academy of Chinese Materia Medica (SM) and the Herbarium of the Kunming Institute of Botany, the Chinese Academy of Sciences (KUN), we found two sheets of a collection made in north-western Yunnan, i.e. Zhongdian Expedition 63-2984 . On the determinavit slip of the sheet in SM, Chen wrote Viola verticillata S. Y. Chen & C. Ho. Obviously the Chinese description and the illustration were based on this sheet. After checking this specimen, we were further sure that it represents a distinct species. From the field record of this collection, we knew the detailed locality and flowering period of the species. In July 2004, the first author made a field trip to the locality, Hutiaoxia (literally meaning Tiger Leaping Gorge), Zhongdian County, north-western Yunnan, and successfully discovered the species. In the field, he found that the plant usually has 1–2 (-4) basal, long petiolate, undivided and widely cordate leaves, which are quite different from the cauline, sessile and linear leaves, such features not seen in the collection of the Zhongdian Expedition 63-2984 mentioned above. The cauline leaves are actually not always entire as described by Chen (1985), but sometimes remotely denticulate in the upper part, and very rarely bifid.

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SPECIES DESCRIPTION Viola dimorphophylla Y. S. Chen & Q. E. Yang sp. nov. (sect. Dischidium Ging. Subsect. Brevicalcaratae W. Beck.) (Figs 1–5). V. verticillata S. Y. Chen & C. Ho in Icon. Corm. Sin., Supp. II: 525, fig. 8905. 1985 (nom. invalid.), non Ortega in Nov. Pl. Descr. Dec. 4: 50. 1797. Type: China: Yunnan: Zhongdian, Hutiaoxia, Shanghutiao, 2400 m, Jinshajiang River valley, sunny grassy and bushy slopes on limestone soils, 10.vii.2004, You-sheng Chen 4268 (holotype, PE; isotypes, BM, E, K); Ibid., 2650 m, 1.vii.1963. Zhongdian Expedition 63-2984 (paratypes, KUN; SM). Diagnosis: Viola dimorphophylla Y. S. Chen & Q. E. Yang affinis V. urophyllae Franch. floribus luteis glabris, calcari brevi, stigmate bilobato, rhizomate brevi dense articulato radices fibras densas numerosas nigro-brunneas emittente, sed differt foliis conspicue dimorphis, eis basalibus longe petiolatis indivisis late cordatis, eis caulinis sessilibus linearibus verticillatis. Description: Similar to V. urophylla in having flowers yellow, glabrous, spur short, stigma slightly bilobed, rhizome short, densely articulate, and fibrous roots numerous, dense and black-brown, but differs by having leaves conspicuously dimorphic, with the basal ones being long petiolate, undivided and widely cordate, and the cauline ones sessile, linear and verticillate. PERENNIAL HERB to 30 cm high, lacking stolons. ROOTSTOCK to 25 mm long, 5 mm in diameter, vertical, densely articulate, with numerous dark-brown fibrous roots. STEMS 1–4, 0.2–1 mm in diameter, glabrous, rarely 1-branched. BASAL LEAVES 1–2 (-4) or withered, long petiolate; petiole 2.5–13 cm long, glabrous; blade chartaceous, widely cordate, usually broader than long, 1–4 ¥ 1.5–5 cm, apex obtuse, base cordate, margin crenate-serrate, deeply green above, densely white hispid, purplish beneath, glabrous. CAULINE LEAVES (3–)5–7 (-10), sessile, linear, glabrous on both surfaces, verticillate, 8–44 ¥ 1–6.5 mm, margin usually entire, sometimes remotely denticulate in upper part, very rarely bifid. STIPULES 2, free, leaf-like when mature, 4–10 mm long, nearly indistinguishable from leaves. FLOWERS yellow, axillary, c. 13 mm in diameter; pedicels 12–35 mm long, slender, glabrous, 2bracteolate near apex; bracteoles very small, c. 1 mm long, linear. SEPALS green, linear, margin entire, apex acuminate, glabrous, 3–4 ¥ 0.25–0.5 mm; sepal appendages very short, glabrous. PETALS glabrous, upper ones oblong-spathulate, 7–10 mm long, 2.5– 3.5 mm wide in upper part, apex rounded; lateral ones oblong-spathulate, 8–11 mm long, 3.5–4 mm wide in

upper part, apex rounded, at throat with 2 black striae; lower petal broadly obovate-spathulate, 7– 9 mm long, 3–4 mm wide in upper part, apex obtuse, at throat with 6–9 black striae, shortly spurred; spur yellowish white, c. 0.5 ¥ 1.2 mm. ovary ovoid, glabrous; style clavate, base geniculate, 1.6–3 mm long; STIGMA capitate, thick, slightly bilobed, glabrous. CAPSULES ovoid or globose, glabrous, 2–2.5 mm in diameter. SEEDS ovoid, 1.5 ¥ 1 mm.

DISCUSSION Viola dimorphophylla is endemic to Zhongdian County, north-western Yunnan, China. It is only known from its type locality, but is fairly common there. Viola dimorphophylla is obviously a member of section Dischidium Ging. subsection Brevicalcaratae W. Beck. by having axillary yellow glabrous flowers, very short spur and bilobed stigma. This subsection comprises 7–9 species in China (Wang, 1991; Huang, 2003), of which V. urophylla Franch., sometimes with three nearly verticillate cauline leaves, perhaps its closest relative. This species is quite common in the type locality of V. dimorphophylla, but we did not see any intermediate forms between them in the field. The flowers and roots of these two species are very similar, but V. dimorphophylla is different from V. urophylla Franch. by having obviously dimorphic leaves, with the basal ones being long petiolate, undivided and widely cordate in outline, and the cauline ones sessile, linear and obviously verticillate. In V. urophylla, the basal leaves are similar to the cauline ones in shape, all long petiolate, and triangular-ovate or widely cordate in outline. Viola dimorphophylla is distinct in the Chinese species of Viola by having verticillate linear leaves, so much so that Chen (1985) established a new subsection, subsection Verticillatae S. Y. Chen under section Dischidium Ging. to accommodate this species (under the name V. verticillata Chen and Ho as aforementioned). Chen (1985) published the new subsection in a key to the Chinese Viola species and did not give a Latin diagnosis, so the publication is invalid. As V. dimorphophylla is so similar to the members of sect. Dischidium subsect. Brevicalcaratae in flower structure, we consider that it is unnecessary to establish an independent subsection for it. We have cultivated some living plants of the new species in the greenhouse to observe its morphology. We found there were a pair of leaf-like but much smaller stipules (c. 3 mm long) borne with other leaves in young plants, but later the two stipules became much larger and nearly indistinguishable from the leaves.

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1 cm B 3 mm

3 mm

A

C

Figure 1. Viola dimorphophylla sp. nov. (Chen 4268). A, habit; B, flower in front view; C, style.

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2

3

4

5

Figures 2–5. Viola dimorphophylla sp. nov. (photographed by You-sheng Chen). Fig. 2, flower in side view. Fig. 3, flower in front view. Fig. 4, habit in flowering. Fig. 5, Viola dimorphophylla, habit in fruiting.

© 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149, 115–119

NEW SPECIES OF VIOLA FROM CHINA

ACKNOWLEDGEMENTS We thank Mr Sun Ying-bao for the drawing, and curators of the herbaria (KUN, SM) who allowed our access to their collections, and two anonymous referees for their invaluable comments on the paper.

REFERENCES Baillon H. 1873. Histoire des Plantes. Paris: Librairie Hachette & Cie. 4: 344–345. Britton NL, Brown A. 1897. Illustrated flora of the northern United States, Canada and the British possessions. New York: Charles Scribner’s Sons. 2: 456. Chen SY. 1985. Violaceae. In: Institute of Botany, Chinese

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Academy of Sciences, ed. Iconographia Cormophytorum Sinicorum, Supplementum II. Beijing: Science Press, 511, 525, fig.8905. (In Chinese). Greuter W, McNeill J, Barrie FR, Burdet HM, Demoulin V, Filgueiras TS, Nicholson DH, Silva PC, Skog JE, Trehane P, Turland J, Hawksworth DL. 2000. International code of botanical nomenclature (St. Louis Code). Königstein: Koeltz Scientific Books. Huang SH. 2003. New species of Viola from Yunnan. Acta Botanica Yunnanica 25: 431–434. Melchior H. 1925. Violaceae. In: Engler A, ed. Die Natürlichen Pflanzenfamilien. Leipzig: Verlag von Wilhelm Engelmann. 21: 359. Wang QR. 1991. Viola L. Flora Reipublicae Popularis Sinicae. Beijing: Science Press, 51, 8–129. (In Chinese).

© 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149, 115–119