Liriodendron L.
Liriodendron is a genus of two species (although many more have been described in the past). One is native to eastern North America (L. tulipifera), the other to eastern Asia (L. chinensis (Hemsl.) Sarg.). Both species are cultivated as ornamentals but the former is by far the commonest and it has been recorded as an escape in Belgium. Their hybrid (‘Liriodendron x chinamerica’; Mabberley 2008) might become significant in horticulture. It is interfertile and reproduces from seed.
Literature:
Andrews S. (1993) Tree of the year: Liriodendron. Int. Dendrol. Soc. Year Book 1992: 15-19.
Hunt D. (ed.) (1998) Magnolias and their allies. Proceedings of an International Symposium, Royal Holloway, University of London, Egham, Surrey, U.K., 12-13 April 1996.
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Meyer F.G. (1971) The two tuliptrees. Amer. Hort. Mag. 50(2): 87-89.
Parks C.R., Miller N.G., Wendel J.F. & McDougal K.M. (1984) Genetic divergence within the genus Liriodendron (Magnoliaceae). Ann. Missouri Bot. Gard. 70(4): 658-666. [available online at: https://www.biodiversitylibrary.org/part/31106#/summary]
Roloff A. & Bärtels A. (2006) Flora der Gehölze (2e Auflage). Ulmer, Stuttgart: 844 p.
Schoenike R.E. (ed.) (1980) Yellow poplar (Liriodendron tulipifera L.): an annotated bibliography to and including 1974. Clemson, Department of Forestry, Clemson University.
Spongberg S.A. (1989) Liriodendron. In: Walters S.M. & al. (eds.), The European Garden Flora, vol. 3. Cambridge University Press, Cambridge: 312-314.