I have had the oddest things come up in my sphagnum (mostly living). In my VFT 'Wilmington, NC' I seem to have either D. rotundifolia or D. prolifera coming up. I swear it looks like prolifera but I do not think it is. I have had these plants come up from seed which I did not have or did not know about:
S. rubra x. prupurea ? seedling
What have you had come up?