Great Egret

Great Egret

Tuesday, 30 August 2016

One of the rarest plants in Canada

Walpole Island First Nation is a fabulous place, full of rare, threatened and endangered species of flora and fauna. Of course to host all of these rarities, there is an abundance of significant habitats as well. Walpole is renowned for its tallgrass prairie, and I have had the privilege of spending a lot of time exploring the wonderful natural areas there over the years, dating back to about the mid 1970s.

One plant I am always excited to see is one of Canada's rarest: the White Prairie Gentian (Gentiana alba). It is a striking yellowish/white flower with fine green markings along the fluted edges. It will partially open, so as to allow pollinators access. This species, at least on Walpole, is in some of the best quality tallgrass prairie/oak savanna habitats.
White Prairie Gentian
It occurs in three known places on Walpole, all of them which are somewhat out-of-the-way. It is interesting to note that even historically it was only known from two other locations in Canada: Northumberland County and Essex County. Those two sites are considered historic, not having been seen for several decades, in spite of searches at known historical locations.

A recent survey of the populations at Walpole totalled 50 plants, with about 40 of them having flowers. That is it...... the entire known Canadian population is just 50 plants, and some years there are even fewer recorded. It is legislated as an Endangered species both provincially and federally, not surprisingly. The localized spots where it occurs are reasonably well protected, although the original population, first found in 1984, is quite shaded and the single surviving plant has not been seen in flower for several years.

At one point during the survey, I only had my point-and-shoot camera, and I got a few shots including this next one. It was the freshest looking of all of the ones we encountered. Most others had at least a bit of brown showing on the petals.

What makes this species toehold in Canada even more precarious is the fact that it sometimes hybridizes with the much more common Bottle or Closed Gentian (Gentiana andrewsii). As its name indicates, it remains closed, and the only way for pollinators to pollinate it is to be a rather robust insect, such as a medium to large bee, having the capability to force its way through the side of the petal.
Bottle Gentian
Clearly the two species are quite different looking, at least in colour, and those hybrids make for some unusual colour combinations.
Gentiana alba X andrewsii

 Some hybrids are mostly closed, with others being at least partly open.
White Prairie Gentian typically flowers in late August, whereas Bottle Gentian typically flowers after mid-September. Of course there are sometimes early or late ones of either species, and if the flowering period overlaps where they both occur, hybrids are more likely.


  1. Allen, this white Prairie Gentian is an excellent species! Thank you for documenting with your great photography and writeup. Last year I found (after searching quite a bit) Fringed and Bottle Gentian at Ojibway and that was tremendously exciting. Good Botanizing! -Dm

    1. Thanks, Dwayne. Gentians are one of the highlights of the late summer/early fall for me, although they sometimes get lost in the overwhelming yellows of sunflower and goldenrod types on the prairie.