Bill, that's exactly what I thought too, but then I see a lot of references saying that it can spread by parts of the plant too, not just the turions or the rhizomes.

https://www.seagrant.wisc.edu/our-w...s-fact-sheets/plants/curlyleaf-pondweed/

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).