Contributed by John B. Nelson, Gary P. Fleming, and Derick B. Poindexter
A genus of about 300 species, herbs and shrubs, mainly temperate, nearly cosmopolitan (except Australia and New Zealand).
Ref: Fleming, Nelson, & Townsend (2011); Floden (2016); Harley et al. In Kadereit (2004); Keener & Davenport (2016); Mulligan & Munro (1989); Nelson (1981); Nelson (2008); Nelson & Fairey (1979); Nelson & Rayner (2014); Poindexter & Nelson (2011); Pringle (2002). Show full citations.