Lilly Propagation

Has anyone heard of propagating some types of lillies from their leaves? I
noticed a guy at a local pond store removing some good leaves. I asked him
what he was doing and he explained that some lillies produce a white node on
the top of the leaf. The other side is where the stem attaches. He said if
you remove the leave and turn it upside down in the water it will form a new
water lilly. I notice one of my tropicals had them and have just tried it.
But I was wondering if there was anything else involved.

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o_o_o_o
/| ,[_____],
|¯¯¯L --O|||||||O-
()_)¯()_) ¯¯¯¯¯ )_)



Thanks,
Ted