A few months ago I was out for a hike along the Thames River near Thorndale. Venturing through a rather boring expanse of Reed Canary Grass and Manitoba Maple, I got to the edge of the river and spotted a patch of Lizard's Tail (Saururus cernuus). The common name for this plant is in reference to the long, showy white flowers which taper and look like a bushy tail...I'm not sure why lizard...it was probably a coin flip between Lizard's Tail or Unicorn's Tail.
This species inhabits river and pond edges, muddy shores and sometimes swamps. It has a distribution in Ontario which roughly aligns with what is considered to be the northern extent of the Carolinian Zone. It is considered vulnerable in Ontario but as the rest of my post indicates, it can be quite common on certain lengths of a watercourse, such as the Thames.
Here is a small stand along the Grand River in Cambridge.
What is interesting is that in fall, when the leaves and stems die back for the winter, they dry a deep reddish-brown hue in colour. This reddish-brown, when viewed from Google Earth creates a very distinct colour signature. The photo below shows the stark contrast between red and the greenish colour of what is predominantly Reed Canary Grass.
Having encountered one of these patches while out for a hike, then extrapolating that reddish brown colour up the river for a few kilometres, it quickly becomes apparent that the Thames River between Thorndale and St. Marys is packed with Lizard's Tail.