Wednesday, May 20, 2015

A note about Trillium grandiflorum (white trillium)

Trillium grandiflorum (white trillium) is putting on a great show this spring. This flower is native to eastern North America (range map here). It is listed as secure in most of its range, but is endangered in Maine and exploitably vulnerable in New York [1], and its status is undetermined in New Brunswick [2]. The species is a member of the family Melanthiaceae.

Trillium grandiflorum
T. grandiflorum is a very distinctive flower, easy to identify. I have already commented quite extensively on this flower in a post I made last summer, including a discussion of its pollinators and its interesting seed dispersal mechanism (myrmechory - ant dispersal).

Trillium grandiflorum population
Where it is not vulnerable to deer predation, T. grandiflorum can form very large, dramatic colonies, like the one pictured above which is in the park portion of the Notre-Dame-des-Neiges cemetery in Montreal (on the west side of the mountain).

Trillium grandiflorum - yes, T. grandiflorum, not T. grandiflorum f. roseum
Sometimes, when people see a trillium like the above, they assume that they are seeing a different variety; there does exist a variety of trillium (T. grandiflorum f. roseum) which is pink. However, this variety is extremely rare, and has a sharper, wavier appearance. This is actually just a regular T. grandiflorum.

Trillium grandiflorum
So if this is a regular T. grandiflorum, why is it pink?

T. grandiflorum is a flower which changes colour as it ages. A pink flower like the above is just an older one, approaching its time of senescence. So when you see a pink individual (or a few pink individuals) among your T. grandiflorum population, just remember that it is more than likely just another T. grandiflorum that happens to be a bit older than the others.

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