William Hudson (1730-1793) named Tofieldia for the British botanist Thomas Tofield (1730–1779).[5] The family Tofieldiaceae was erected by Armen Takhtajan in 1995.[6] Molecular phylogenetic studies of DNA sequences have shown it to be the second diverging clade in Alismatales, after the most basal clade, the family Araceae.[7] Before the segregation of Tofieldiaceae was confirmed by cladistic methods, its genera had usually been assigned to Nartheciaceae,[8]Liliaceae,[9] or Melanthiaceae. Tofieldiaceae is recognized by the Angiosperm Phylogeny Group in their APG III system of plant classification.
The circumscription of genera in Tofieldiaceae has been controversial. Many authors do not recognize Triantha as a separate genus from Tofieldia.[8][10][11] A few authors have sunk other genera into Tofieldia as well.[12] A phylogenetic analysis, based on two nuclear genes and ten chloroplast genes, has confirmed that all five of the genera are monophyletic and that Triantha and Tofieldia are close sister taxa.[13]
The following phylogenetic tree is based on a DNA paper that was published in 2011,[13] modified to accommodate the transfer of the species in Isidrogalvia to Harperocallis.
↑Vernon H. Heywood, Richard K. Brummitt, Ole Seberg, and Alastair Culham. Flowering Plant Families of the World. Firefly Books: Ontario, Canada. (2007). ISBN978-1-55407-206-4.
↑Anthony Huxley, Mark Griffiths, and Margot Levy (1992). The New Royal Horticultural Society Dictionary of Gardening. The Macmillan Press,Limited: London. The Stockton Press: New York. ISBN978-0-333-47494-5 (set).
↑Umberto Quattrocchi. 2000. CRC World Dictionary of Plant Names volume IV. CRC Press: Boca Raton; New York; Washington,DC;, USA. London, UK. ISBN978-0-8493-2673-8 (set). (see External links below).
↑Tofieldiaceae. At: International Plant Names Index. (see External links below).
↑ 8.08.1Minoru N. Tamura. 1998. "Nartheciaceae" pages ??. In: Klaus Kubitzki (general editor) with Klaus Kubitzki, Herbert F.J. Huber, Paula J. Rudall, Peter F. Stevens, and Thomas Stützel (volume editors). The Families and Genera of Vascular Plants volume III. Springer-Verlag: Berlin;Heidelberg, Germany. ISBN978-3-540-64060-8 (vol. III).
↑Frederick H. Utech, Loran C. Anderson, and John C. Packer. 2002. pages 5-6. In: "Liliaceae". pages ??. In: Flora of North America Editorial Committee. Flora of North America vol. 26. Oxford University Press: UK. ISBN978-0-19-513729-3 (vol. 22). (see External links below).
↑David J. Mabberley. 2008. Mabberley's Plant-Book third edition (2008). Cambridge University Press: UK. ISBN978-0-521-82071-4
↑Armen L. Takhtajan (Takhtadzhian). Flowering Plants second edition (2009). Springer Science+Business Media. ISBN978-1-4020-9608-2.
↑Wendy B. Zomlefer. 1997. "The genera of Tofieldiaceae in the southeastern United States". Harvard Papers in Botany. 2:179-194.
↑ 13.013.1Hiroshi Azuma and Hiroshi Tobe. 2011. "Molecular phylogenetic analyses of Tofieldiaceae (Alismatales): family circumscription and intergeneric relationships". Journal of Plant Research124(3):349-357. doi:10.1007/s10265-010-0387-5