Toad-lilies, the common name given to the genus Tricyrtis, have been the source of much consternation to people or institutions who like to have the correct name associated with the plants in their garden or nursery–including botanical gardens. As Dawn Parish of the Stephen F. Austin State University Mast Arboretum (in Texas) writes in her (no longer online) article “Toad Lilies–Gems of the Fall”,
Toad lilies are notoriously mixed up in the trade.
Indeed, according to the nomenclatural notes in older print versions of the Royal Horticultural Society‘s Plant Finder, at least five different species have been sold under the name Tricyrtis macropoda!
The same pattern of horticultural confusion can be seen with a number of other genera, including Hydrangea, Epimedium and some Acer species. The explanation of why delves into a curious mix of horticulture, botany and plant exploration. Despite my belief that a book would be necessary to be comprehensive about on the subject, I’ll try my best to summarize.
In the case of Tricyrtis and the other species, the common thread begins with Japan, but it could also be another set of geographically-related groups of plants. When a cultural, centuries-old tradition of plant breeding is mixed with plants that either readily hybridize or show tremendous variation in physical traits, the result is a high number of cultivated varieties, occasionally found growing in semi-natural or natural settings. In the case of these Japanese plants, Western plant explorers returned to Europe with these cultivars (of human origin) that they believed to be species (of evolutionary origin). Plant taxonomists incorrectly classify and describe some of these plants as proper species. Books and articles are published describing the new plants. Eventually, it is uncovered that the species are actually cultivated varieties in Japan, and not proper species. Papers are written making the necessary corrections for the scientific record. In the meantime, however, both the plants and the misinformation associated with the plants are propagated throughout the nursery trade, the scientific community and the gardening public due to the earlier publications and “mindshare” of being the first name associated with a particular recognizable plant. Finally, a few dedicated people (or a single person) devote a massive amount of time trying to figure out the whole mess, hopefully writing a book that offers much-needed clarity through documenting the human, horticultural and botanical histories of the plants. To my knowledge, no book or similar reference work yet exists for Tricyrtis.
It’s a stunning case-study of the propagation of misinformation that would likely interest an enterprising information scientist. I fear that although my summary is lengthy, it is still overly-simplistic – it neglects to mention the same cultivar being sold in the trade under both its English cultivar name and its Japanese one, for example. As I mentioned, however, it would require a book to fully illustrate the difficulties arising from the question, “What name do we use to represent this plant?”
Updated April 28, 2017: For more on the topic, see Dennis Carey and Tony Avent’s article, Tricyrtis – Perennial Toad Lilies for the Woodland Garden.