Tofieldiaceae is a Household of flowering plants from the monocot order Alismatales. The family is divided into four genera, which collectively comprise 28 known species (Christenhusz & Byng 2016). They’re little, herbaceous plants, largely of arctic and subarctic areas, but a few extend further south, and one genus is endemic to northern South America and Florida. Tofieldia pusilla may be grown as an ornamental.

William Hudson (1730-1793) called Tofieldia for the British botanist Thomas Tofield (1730–1779). The household Tofieldiaceae was erected by Armen Takhtajan in 1995. Molecular phylogenetic studies of DNA sequences have revealed it to be the next largest clade in Alismatales, following the most basal clade, the household Araceae. Ahead of the segregation of Tofieldiaceae has been supported by cladistic techniques, its genera had been delegated to Nartheciaceae, Liliaceae, or Melanthiaceae. Tofieldiaceae is recognized by the Angiosperm Phylogeny Group within their APG III system of plant classification.

The circumscription of genera in Tofieldiaceae has been contentious. Many writers don’t recognize Triantha as a distinct genus from Tofieldia. A couple of writers have sunk other genera to Tofieldia also. A phylogenetic analysis, according to two nuclear genes and ten chloroplast genes, has confirmed that five of those genera are monophyletic and that Triantha and Tofieldia are near sister taxa.

Description

Herbaceous perennials. Leaves equitant (distichous and overlapping), isobifacial. Inflorescence a raceme. Calyculus present. Tepals free. Fruit a capsule, usually septicidal.