There was a revision of the genus; Annals of the Missouri Botanical Garden, pp. 79–191 Vol 94, Issue 1 (April 2007)
Link to abstract here;
http://tinyurl.com/6oz4sn If you search on Google for "Flora of China draft Ainsliaea" you should get an HTML file with a key, including Korea and Japan if the species is present there also.
Many of the species are all highly attractive garden plants, like Prenanthes, Cacalia, Polymnia, etc.
Aaron Floden
Knoxville, TN