Wow,
What a great site.. Yes, I think it is an Imperial Taro as I found a couple of sites with some pics.. I took another look, and some of the stocks are dark, but it matches the Imperial really close. I guess if things got really tough, I could even eat it (POI)..............
--THANK YOU ALL..
I added a couple more pics of my mysterious plant that is extemely aggressive.. Kinda like a water bamboo as it sends out shoots with puppies all over my pond.. It also has a very distinctive smell-- not bad, not good, just very "GRASSY" for lack of a better way to describe it.. It grows very fast in the summer and did not set back in our mild S. Calif winter (but did stop growing), and will grow free floating too (but stays much smaller leaved).. Basically, it's very hard to kill, even in my compost pile where 75+% of it ended up this summer..It even tried to take root there !!
Thanks again and if I get the opportunity to share anything I have learned in my 40 yrs of ponding, I will do my best to help.. I'm pretty good at maintaining crystal clear water that "sparkles" much of the time, and understand what it takes to keep a way over-stocked pond alive even in the warmer months.. It can be a real challenge, especially if you go on vacation..
Tony