Mystery plant Id. please!

[mcp]

Recieved this mystery plant in with  some others on  a purchase from ebay. All it said was it was a mystery. I know it hasa to be fairly common or it would not have been free. I stuck it in a pot with some pea gravel it grew like crazy . Must take a lot of nutrients out of water. Should i keep or throw it in the compost pile? Thannks for all the replys in advance.



Here is another close up.

[Joyce]

Looks like some kind of Water Plantain to me...probably small Water Plantain...Alisma subcordatum:
http://www.ct-botanical-society.org/galleries/alisma.html

[andrew davis]

Plantain drops humungous numbers of seed that will drift into every other pot and deep water, and sprout. Horrible stuff to weed.

Rip the seedheads out before they start dropping seed...

Regards, andy
tp://www.members.aol.com/abdavisnc/swglist.html