Clematis L.

Clematis is a genus with ca. 300 species in temperate regions of the world (Xie & al. 2011). The genus is particularly rich in China where 147 are known, 93 of them endemic (Wang & Bartholomew 2001). A single species is native in Belgium, C. vitalba L. (Lambinon & Verloove 2012).

Clematis is extremely diverse and has been divided in several smaller genera. However, molecular data seem to support a broad generic concept (Xie & al. 2011). Also, infrageneric classifications based on morphology does not seem to be supported. Further genetic studies have shown that Clematis is in fact very closely related with Anemone (Lehtonen & al. 2016), especially if the latter is accepted in a broad sense (i.e., including, among others, Hepatica and Pulsatilla). However, pending further evidence, Clematis is here treated in its traditional sense.

The genus is very popular in horticultural and many species are valued as ornamentals. Useful accounts with identification keys for Clematis in cultivation in Europe are provided by, for instance, Brandenburg (1989), Roloff & Bärtels (2006) and Jäger & al. (2008). More than 50 species are upheld by Brandenburg l.c. Their recognition, however, is often a difficult matter. Hybrids and cultivars are widespread in cultivation. In some cases, especially for large-flowered hybrids, plants can only be assigned to cultivar-groups (Roloff & Bärtels l.c., Brandenburg l.c.). Many of the cultivated taxa (including several of the more popular hybrids!) freely reproduce from seed and are regularly observed as escapes, sometimes even without parental plants growing nearby. In the absence of flowers such saplings are hard to identify. Therefore, in addition to the taxa included in this account several others probably also occur in the wild but their correct identity should be assessed.

Native Clematis vitalba has considerably enlarged its distribution area in Belgium in the past decades and now occurs in regions where it is not originally native. It is not impossible that some of these records refer to cultivars, hybrids or even different, related species. The Vitalba Group in horticulture includes, in addition to C. vitalba, also C. ligusticifolia Torrey & A. Gray, C. potaninii Max. and C. virginiana L. (Donald 2015).

A useful, copiously illustrated account for the genus in Germany (wild as well is horticulture) is available here: An overview of all species and cultivars available in horticulture is provided by RHS at:

Numerous societies offer information on Clematis in cultivation. Links to some of the more important follow here under:
American Clematis Society:
Clematis on the Web:
International Clematis Society:
British Clematis Society:

1 Stem erect, not climbing === 2
Stem climbing === 3

2 Leaves entire. Sepals blue. Flowers usually solitary and terminal, nodding === Clematis integrifolia
Leaves once pinnate, with 5-7 leaflets. Sepals white. Flowers numerous in axillary, erect panicles === C. recta

3 Sepals yellow === C. tangutica
Sepals bluish, white or purplish === 4

4 Leaves predominantly ternate (sometimes the upper undivided) === 5
Leaves pinnate === 6

5 Sepals white or pink. Flowers 4-6 cm across, on previous year’s shoots === C. montana
Sepals dark violet-blue or white. Flowers 10-14 cm across, on current year’s shoots === C. xjackmanii

6 Sepals blue to purple. Beak of achene glabrous in fruit. Flowers solitary or up to three === C. viticella
Sepals creamy white. Beak of achene plumose in fruit. Flowers in multi-flowered panicles === 7

7 Sepals hairy on both surfaces. Leaves once pinnate (native) === C. vitalba
Sepals hairy only on lower surface. Leaves twice pinnate === C. flammula


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Brummitt R.K. (2000) Inclusion of Clematopsis Hutch. in Clematis L. (Ranunculaceae). Kew Bull. 55(1): 97-108.

Daumann E. & Slavikova Z. (1968) Zur Blütenmorphologie der tschechoslowakischer Clematis-Arten. Preslia 40: 225-244.

Donald D. (2015) International Clematis Register & Checklist 2002 5th Supplement. Available online at:

Essig F.B. (1992) Seedling morphology in Clematis (Ranunculaceae) and its taxonomic implications. Sida 15: 377-390. [available online at:]

Essig F.B. (2004) A preliminary analysis of Clematis (Ranunculaceae) in sub-Saharan Africa. Sida, Contrib. Bot. 21(2): 861-877. [available online at:]

Fernández Carvajal M.C. (1986) Clematis. In: Castroviejo S. (ed.), Flora Iberica, vol. 1. Real Jardín Botánico, Madrid: 268-272. [available online at:]

Gooch R. (2001) Clematis: The Complete Guide. Crowood Press: 184 p.

Gooch R. & Gooch J. (2011) Clematis An Essential Guide Crowood Press: 256 p.

Grey-Wilson C. (2000) Clematis the genus. Portland, Oregon: Timber Press.

Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.

James J.F. (1883) Revision of the genus Clematis of the United States. J. Cincinnati Soc. Nat. Hist. 6: 118-135.

Johnson M. (2001) The genus Clematis. Sodertalje, Sweden: Magnus Johnsons Plantskola AB xiv + 896 p.

Jonsell L. (2001) Clematis. In: Jonsell B. (ed.), Flora Nordica, vol. 2. The Bergius Foundation, Stockholm: 297-299.

Keener C.S. & Dennis W.M. (1982) The subgeneric classification of Clematis (Ranunculaceae) in temperate North America north of Mexico. Taxon 31: 37-44.

Kuntze O. (1885) Monographie der Gattung Clematis. Verhandlungen des Botanischen Vereins der Provinz Brandenburg 26: 83-202.

Lambinon J. & Verloove F. (2012) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Sixième édition. Jardin botanique national de Belgique, Meise: CXXXIX + 1195 p.

Lehtonen S., Christenhusz M.J.M. & Falck D. (2016) Sensitive phylogenetics of Clematis and its position in Ranunculaceae. Botanical Journal of the Linnean Society 182: 825-867. [available online at:

Lloyd C. (1989) Clematis. United Kingdom, Viking: 232 p.

Miikeda O. (2007) Phylogeny and evolution of native Clematis  based on molecular (DNA) analysis. Clematis 2007: 161-163.

Miikeda O., Kita K., Handa T. & Yukawa T. (2006) Phylogenetic relationships of Clematis (Ranunculaceae) based on chloroplast and nuclear DNA sequences. Botanical Journal of the Linnean Society 152: 153-168.

Pringle J.S. (1973) The cultivated taxa of Clematis Sect. Atragene (Ranunculaceae). Baileya 19: 49-83.

Pringle J.S. (1997) Clematis. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 3. Oxford University Press, New York-Oxford: 158-176. [available online at:]

Roloff A. & Bärtels A. (2006) Flora der Gehölze (2e Auflage). Ulmer, Stuttgart: 844 p.

Shi J.-H. & Li L.-Q. (2003) Leaf epidermal feature in Clematis (Ranunculaceae) with reference to its systematic significance. Acta Botanica Sinica 45: 257-268. [available online at:]

Snoeijer W. (1992) A suggested classification for the genus Clematis. Clematis 1992: 7-20.

Spach E. (1839) Trib. Clematideae. Histoire des Naturelle Végetaux. Phanerogames. Paris. 7: 257-284. [available online at:]

Tamura M. (1955) Systema Clematidis Asiae Orientalis. Science Reports. Osaka University 4: 43-55.

Tamura M. (1956) Notes on Clematis of eastern Asia III. Acta Phytotaxonomica Geobotanica 16: 79-83. [available online at:]

Tamura M. (1987) A classification of genus Clematis. Acta Phytotaxonomica Geobotanica 38: 33-44. (in Japanese).

Tamura M. (1995) Clematis. In: Hiepko P. (ed.), Die Natürlichen Pflanzenfamilien (2nd ed.) 17a (4), Berlin: Duncker und Humbolt: 368-387.

Toomey M. & Leeds E. (2001) An Illustrated Encyclopedia of Clematis. Charles Chesshire (Timber Press): 426 p.

Tutin T.G. (rev. Akeroyd J.R.; 1993) Clematis. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 1. (2nd ed.). Cambridge University Press, Cambridge: 266-267.

Wang W.-T. (2000) Notes on the genus Clematis (Ranunculaceae): 1. (in Chinese). Acta Phytotax. Sin. 38(4): 305-336. [available online at:]

Wang W.-T. (2000) Notes on the genus Clematis (Ranunculaceae): 2. (in Chinese). Acta Phytotax. Sin. 38(5): 401-429. [available online at:]

Wang W.-T. (2000) Notes on the genus Clematis (Ranunculaceae): 3. (in Chinese). Acta Phytotax. Sin. 38(6): 497-514. [available online at:]

Wang W.-T. (2001) Notes on the genus Clematis (Ranunculaceae): 4. (in Chinese). Acta Phytotax. Sin. 39(1): 1-19. [available online at:]

Wang W.-T. (2001) Notes on the genus Clematis (Ranuculaceae): 5. (in Chinese). Acta Phytotax. Sin. 39(4): 309-336. [available online at:]

Wang W.-T. (2002) A revision of Clematis sect. Cheiropsis (Ranunculaceae). Acta Phytotax. Sin. 40(3): 193-241. [available online at:]

Wang W.-T. (2003) A revision of Clematis sect. Clematis (Ranunculaceae). Acta Phytotax. Sin. 41(1): 1-62. [available online at:]

Wang W.-T. (2003) A revision of Clematis sect. Clematis (Ranunculaceae) (continued). Acta Phytotax. Sin. 41(2): 97-172. [available online at:]

Wang W.-T. (2004) A revision of Clematis sect. Aspidanthera (Ranunculaceae). Acta Phytotaxonomica Sinica 42: 1-72, 97-135. [available online at: and]

Wang W.-T. (2004) A revision of Clematis sect. Brachiatae (Ranunculaceae). Acta Phytotaxonomica Sinica 42: 289-332. [available online at:]

Wang W.-T. (2004) A revision of Clematis sect. Pseudanemone (Ranunculaceae). Acta Phytotax. Sin. 42(5): 385-418. [available online at:]

Wang W.-T. (2006) Notes on the genus Clematis (Ranunculaceae) (VI). Acta Phytotax. Sin. 44(3): 327-339. [available online at:]

Wang W.-T. (2006) A revision of Clematis sect. Meclatis (Ranunculaceae). Acta Phytotax. Sin. 44(4): 401-436. [available online at:]

Wang W.-T. (2006) A revision of Clematis sect. Naraveliopsis (Ranunculaceae). Acta Phytotaxonomica Sinica 44: 670-699. [available online at:]

Wang W.-T. (2007) A revision of Clematis sect. Viticella (Ranunculaceae). Guihaia 27(1): 1-28. [available online at:

Wang W.-T. (2016) A revision of Clematis sect. Pterocarpa (Ranunculaceae). Guihaia 26: 341-344. [available online at:

Wang W.-T. & Bartholomew B. (2001) Clematis. In: Zu Z.-Y. & Raven P., Flora of China, vol. 6. Beijing: Science Press & St. Louis: Missouri Botanical Garden Press. 97-165. [available online at:]

Wang W.-T. & Li L.-Q. (2005) A new system of classification of the genus Clematis (Ranunculaceae). Acta Phytotaxonomica Sinica 43: 431-488. (in Chinese with English abstract). [available online at:]

Wang W.-T. & Li L.-Q. (2005) A revision of Clematis sect. Fruticella (Ranunculaceae). Acta Phytotax. Sin. 43: 193-209. [available online at:]

Wang W.-T. & Xie L. (2007) A revision of Clematis sect. Tubulosae (Ranunculaceae). Acta Phytotaxonomica Sinica 45: 425-457. [available online at:]

Xie L., Wen J. & Li L.-Q. (2011) Phylogenetic analyses of Clematis (Ranunculaceae) based on sequences of nuclear ribosomal ITS and three plastid regions. Syst. Bot. 36(4): 907-921.

Yang T.Y.A. & Moore D.M. (1999) A revision of the Viorna group of species (section Viorna sensu Prantl) in the genus Clematis (Ranunculaceae). Systematics and Geography of Plants 68: 281-303.

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith