There's been a lively e-mail discussion going on between a number of us at the BioPark. Marla at the BioPark office has been publishing a "What's Bloooming" piece for social media every week. This week she chose the colorful Zauschneria in the beds either side of the conservatories.
As it turns out, our plants were once considered Z. canum, but research in recent years has shown that it really needs to be treated as a species of Epilobium.
That said, this brings up the whole question of what is a species. A recent online piece ducked the issue by going with "segments of separately evolving metapopulation lineages." True, it defuses the tricky problem of what features or collection of differences are significant enough to define a species. This definition also allows for the use of different feature sets depending on the taxa involved and the research in question.
Good to know that the species question is still open even 50 years after I took Dr. Spellenberg's Plant Biosystematics class in the spring of 1975.