Thalictrum L.
Thalictrum is a genus with 120-200 (Mabberley 2008) or as many as 330 species (Cai & al. 2009). Most species occur in the northern hemisphere but some extend to tropical America and Africa. Only two species are native in Belgium: Thalictrum flavum L. and T. minus L. (Lambinon & Verloove 2012). Thalictrum is monophyletic but the current subgeneric classification is in need of revision (Ro & McPheron 1997; see also Cai & al. 2009). About 21 species are cultivated as ornamentals in Europe but rather few are more or less frequent in cultivation (Miller 1989, Jäger & al. 2008; see also Jonsell 2001, Stace 2010). Two species have been recorded as escapes in Belgium and an additional species (Thalictrum delavayi Franch., the most frequent in cultivation according to Mabberley 2008) should be looked for. Like Thalictrum aquilegiifolium it has pale purplish sepals but these are much longer than the stamens.
1 Flowers lilac or pinkish. Filaments in upper part at least as wide as anthers. Achenes winged, pendent === Thalictrum aquilegiifolium
Flowers yellowish. Filaments thin, narrower than anthers. Achenes not winged, erect === 2
2 Inflorescence diffuse. Stamens drooping. Leaf blade ca. as long as wide (native) === T. minus
Inflorescence dense. Stamens erect. Leaf blade usually longer than wide === 3
3 Leaves glaucous, with very prominently raised veins on lower side. Stipules always absent. Not rhizomatous === T. speciosissimum
Leaves green, veins not raised. Stipules present. Rhizomatous (native) === T. flavum
Literature:
Boivin B. (1944) American Thalictra and their Old World allies. Rhodora 46: 337-377, 391-445, 453-487.
Boivin J.R.B. (1945) Notes on some Chinese and Korean species of Thalictrum. J. Arnold Arbor. 26: 111-118.
Cai Y., Li S., Liu Y., Quan S., Chen M., Xie Y., Jiang H., Wei E., Yin N., Wang L., Zhang R., Huang C., He X.-H. & Jiang M. (2009) Molecular phylogeny of Ranunculaceae based on internal transcribed spacer sequences. African Journal of Biotechnology 8(20): 5215-5224. [available online at: http://www.ajol.info/index.php/ajb/article/viewFile/65953/53657]
Emura K.M.H. (1972) Cytotaxonomical studies on the genus Thalictrum in Eurasia with special reference to Japanese species. Journal of the Faculty of Science III 11: 93-133.
Fu D.Z. & Zhu G. (2001) Thalictrum. In: Wu Z.Y. & Raven P.H. (eds.), Flora of China, Vol. 6. Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis: 282-302. [available online at: http://flora.huh.harvard.edu/china/PDF/PDF06/THALICTRUM.pdf]
Hand R. (2001) Revision der in Europa vorkommenden Arten von Thalictrum subsectio Thalictrum (Ranunculaceae). Bot. Natursch. Hessen, Beiheft 9: 358 p. [available online at: http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/25339]
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.
Jonsell B. (2001) Thalictrum. In: Jonsell B. (ed.), Flora Nordica, vol. 2. The Bergius Foundation, Stockholm: 312-321.
Lambinon J. & Verloove F. (avec coll. Delvosalle L., Toussaint B., Geerinck D., Hoste I., Van Rossum F., Cornier B., Schumacker R., Vanderpoorten A. & Vannerom H.) (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.
Lecoyer J.C. (1885) Monographie du genre Thalictrum. Bulletin de la Société Royale de Botanique de Belgique 24: 78-315.
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Miller D.M. (1989) Thalictrum. In: Walters S.M. & al. (eds.), The European Garden Flora, vol. 3. Cambridge University Press, Cambridge: 347-349.
Montserrat P. (1986) Thalictrum. In: Castroviejo S. & al. (eds.), Flora Iberica, vol. 1. Real Jardín Botánico, Madrid: 387-401.
Ro K.-E. & McPheron B.A. (1997) Molecular phylogeny of the Aquilegia group (Ranunculaceae) based on internal transcribed spacers and 5.8S nuclear ribosomal DNA. Biochemical Systematics and Ecology 25(5): 445-461.
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.