Rodger, Flora of North America has a key for North American species. It's useless for Eurasian species of course. http://efloras.org/florataxon.aspx/… Nhu On Tue, Jul 12, 2011 at 5:12 PM, <totototo@telus.net> wrote: > On 11 Jul 2011, at 21:51, Roy Herold [NW of Boston] wrote: > > BTW, does anyone know of an easily accessible (sc. online, in English) key > to > the genus Asarum? I grew "Asarum grandiflorum" from RHS seed many years > ago, > but bedamned if I can see any difference from our local A. caudatum. > >