Here is a picture of a four-petalled White Trillium taken at our cottage on Paudash Lake. It is the only one I have ever seen. How rare are they?
Note: These trilliums are quite rare. It is only the second one I’ve heard of in Peterborough County. That being said, trilliums seem to show a fair amount of chromosomal variation, and mutations are not uncommon. There is a tendency of some to show white and green patterns in the petals, for example. One of the pictures below shows a trillium with 12 petals!