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).
ID notes:Stachys is a technically “difficult” genus with species often separated by fairly subtle morphological characters. The genus is in need of modern molecular systematic work to clarify phylogenetic relationships. As now circumscribed, it presents numerous challenges in identification using morphological characters because many species exhibit pronounced variation in leaf blade size or shape, petiole length, and pubescence. As a rule, plants growing in open habitats (sun forms) are stricter, narrower-leaved, shorter-petioled, and/or more pubescent than plants of the same species growing in shade (shade forms). In addition, the shape and length of calyx lobes, which are critical in distinguishing among species, change to some extent during the growing season. Therefore it is essential to obtain material in fruiting or at least late flowering condition for the most reliable assessment of these characters."
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.