Liatris Gaertner ex Schreber
Liatris is a New World genus and counts 37 species that are distributed from North America to Mexico and the West Indies (Nesom 2006). A few species are cultivated as ornamentals (Dress 1959 and Jäger & al. 2008 are particularly helpful; see also Galloway & Cullen 2000) but probably only one, L. spicata (L.) Willd., is widespread in cultivation. It has been recorded as an escape in Belgium.
The identity of every individual population of Liatris requires careful checking since most of the species in cultivation are much alike. Only the identity of a single population from Mol-Europawijk has been critically assessed.
Literature:
Dress W.J. (1959) Notes on the cultivated Compositae, 3. Liatris. Baileya 7: 23-32.
Gaiser L.O. (1946) The genus Liatris. Rhodora 48: 165–183, 216–263, 273–326, 331–382, 393–412. [available online at: http://www.biodiversitylibrary.org/item/14518#page/1/mode/1up]
Gaiser L.O. (1950a) Chromosome studies in Liatris. I. Spicatae and Pycnostachyae. Amer. J. Bot. 37: 122–135.
Gaiser L.O. (1950b) Chromosome studies in Liatris. II. Graminifoliae and Pauciflorae. Amer. J. Bot. 37: 414–423.
Gaiser L.O. (1950c) Chromosome studies in Liatris. III. Punctatae. Amer. J. Bot. 37: 763–777.
Gaiser L.O. (1950d) Evidence for intersectional field hybrids in Liatris. Evolution 5: 52–67.
Galloway A.A. & Cullen J. (2000) Liatris. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 662-663.
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.
Menhusen B.R. (1963) Variation in the Punctatae Series of the Genus Liatris (Compositae). Ph.D. dissertation. University of Kansas.
Nesom G.L. (2005) Infrageneric classification of Liatris (Asteraceae: Eupatorieae). Sida 21: 1305–1321. [available online at: http://www.guynesom.com/LiatrisInfragClass.pdf]
Nesom G. (2006) Liatris. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 21. Oxford University Press, New York-Oxford: 512-535. [available online at: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=118496]
Nesom G.L. & Stucky J.M. (2004) Taxonomy of the Liatris pilosa (graminifolia) group (Asteraceae: Eupatorieae) Sida 21: 815–826.
White M. & Nesom G.L. (2012) Two intersectional hybrids in Liatris (Asteraceae) from east Texas. Phytoneuron 2012-21: 1–6. [available online at: http://www.phytoneuron.net/PhytoN-Liatrishybrids.pdf]