17. Veronicastrum Heist. ex Fabr.
About 20 species,
temperate North America, Asia.
The genus Veronicastrum
traditionally was considered to comprise only two species (one in Asia, the
other in North America), but Yamazaki (1957) expanded the generic concept to
include about 18 additional Asian species previously classified into the genus Botryopleuron
Hemsl. Molecular studies (Albach et al., 2004) and the unusual (for the tribe)
chromosomal base number of (Albach et al., 2008) lend support for the
expanded concept of the genus.