This past weekend, I attended Botany BC for the fourth time. We explored areas around Metchosin and Sooke, where plant communities ranged from beaches to montane forests and from bogs to Quercus garryana woodlands without traveling significant distances. On Saturday, I participated in one of the hikes along the San Juan and Jordan ridges, where we walked mostly through montane forest interspersed with open bogs. One of the species I had hoped to see again at these boggy sites was this diminutive annual species commonly known as the swamp gentian. This would be the (undocumented) southern extent of its range in Canada. To the south, this species is known only from a couple counties in Washington (where it is a state-sensitive species). However, the species is much more common in British Columbia and Alaska, though it is almost always found within 50km (30 miles) from the coast. Two exceptions are north of Anchorage from sites in and around Denali National Park, and, intriguingly, a record from the extreme southeast corner of British Columbia at Procter Lake. This suggests that Montanan, Idahoan and Albertan botanists should keep an eye out for it in adjacent districts.
Unfortunately, I didn’t spot the gentian on our field trip (and am uncertain if anyone else did either). These photographs were taken last year at the same time of year, but are from Pure Lake Provincial Park on Graham Island (Haida Gwaii), where I spent a couple contented hours in the boggy environs. I believe it was the first time I encountered the species, though I have to note that one of the benefits of getting older and forgetting what I’ve seen in the past is the joy of discovering something new for the second or third time.
Gentiana douglasiana is a sun-loving wetland species. It is a small curiosity, perhaps, that it is an annual life-cycle species growing in a stressful environment. I more often associate bogs with slow-growing species that do a long-term investment in the maintenance of a persistent individual (while annual species instead invest in many seeds that are dormant in the harshest conditions). In order for an annual species to persist in an always-stressful environment, one supposes that it would need reproductive certainty from year to year, and that seems to be borne out. In the early 1980s, Sheila Douglas studied floral colour patterns and pollinator attraction in bog habitats (in the nearby Drizzle Lake Ecological Reserve). She classified the pollinators into 12 loose groups. Of the 14 plant species she investigated, Gentiana douglasiana was the only annual species, and it had the highest number of her artificial groups visiting the species: 9 of the 12. This hints that Gentiana douglasiana evolved to be a generalist with respect to pollinators, perhaps to guarantee pollinator visitation and presumably higher reproductive success every year. It would of course need further study (see: S. Douglas. 1983. Floral color patterns and pollinator attraction in a bog habitat. Canadian Journal of Botany. 61(12):3494-3501. 10.1139/b83-394 ).