Tetrachondraceae Skottsberg ex Wettstein.
A family of 2 genera, Polypremum and Tetrachondra (Oxelman et al. 1999), and 3 species, perennial herbs, of s. North America south to South America, and New Zealand. The assignment of Polypremum to family has been controversial, with placement formerly in Loganiaceae or Buddlejaceae. A recent molecular analysis strongly suggests that its closest relationship is with Tetrachondra (Oxelman et al. 1999), and the treatment followed here reflects the current general consensus. Some prefer to treat it in the monospecific Polypremaceae (Reveal 2011).