Branched bartonia (ssp. paniculata) COSEWIC assessment and status report: chapter 11

Summary of Status Report

Branched bartonia is rare in the province due to the limited number of sites known (7 sites known but perhaps only 6 extant), its estimated small population (perhaps 500 or at most 1000 plants; this upper value is highly speculative), its small geographical distribution within Ontario, the significant 600 km distance to the main range of the species, and the plant's specialized habitat. Branched bartonia is a very small cryptic species that is easily overlooked -- even during specific searches for the species. Within its small range are other areas of apparently suitable habitat that could have undiscovered populations. However, many small bogs within the Muskoka-Georgian Bay region have been surveyed and the species has not been found. Being an annual plant, it may not be found above ground at a site in a particular year but still be present in the seed bank.

Sites 5 and 6 are being taken over by an invasive shrub that could threaten branched bartonia at these sites. At Site 2, the species could not be re-confirmed in 2002 and may have disappeared. The former location of the population is adjacent to a railway embankment where any widening could eliminate the site.

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