I'm going through iNaturalist and GBIF to try to figure out the total known number of native horsetail species (genus Equisetum) in our region. Pojar and Mackinnon 2014 contains 4: E. arvense, E. fluviatile, E. hyemale, and E telmatiea. These show up for the top 6 most observed species on GBIF for the PNW region (Vancouver Island to Southern Oregon)... along with E. braunii (appears to actually be a subspecies of telmatiea) and E. praeltum (another name for E. hyemale). iNaturalist appears to return more results for the 4 identified in P&M. And also plenty of other species? Perhaps much of this is just misidentification or outdated taxonomy, and there's only 4 main species out in the PNW... or is the field guide outdated? All that said, how many native Equisetum species do we actually have in our region? Does anyone know?
E-Flora BC shows 14 Equisetum species. I'm not sure if they are all present in BC or "our region" (need definition), since I didn't read any of the detailed descriptions.
Worth adding that E. braunii (formerly E. telmateia subsp. braunii) and E. praealtum (formerly E. hyemale subsp. affine) are now both accepted as distinct species by Plants of the World Online; both are native in BC, while the respective European species they used to be included in (E. telmateia and E. hyemale) are no longer accepted for the BC flora. These changes are quite recent, so won't show up yet in a lot of publications.
Ah. I guess by "our region," I'm accustomed to the P and M definition: Pacific Northwest coastal->inland Cascade mountain region from Eugene, Oregon, to Anchorage, Alaska. My GBIF bounding box only goes from the top of Vancouver Island to the California border, though. Essentially: Southwest BC, western Washington, western Oregon.
Luckily, given all the diversity, nothing appears to be endangered! I guess they should all be fine, assuming that the marshland habitats in BC aren't shrinking (right?).
