Riccia is both fabulous and terrible. Wrapped around rocks or pieces of slate or branches of wood and confined in place with fine netting it is stunning ground cover or "leaves" as it grows out from between the holes in the net. The problem being that it never STOPS growing. It's like a lawn, it has to be tended constantly or it escapes and starts to take everything over.
duckweed on the other hand is OF THE DEVIL. I have orated on this topic before so will omit further detail. Even more than riccia it is indestructible and invasive, on the other hand aside from the quasi-medicinal uses mel mentions it has no redeeming value whatever. Once you get the tiniest speck of it in a tank you will never be free of it again short of cleansing with a flamethrower, and I am not prepared to swear it could not survive even that. It is in the "nuke it from orbit, that's the only way to be sure" category. OF THE DEVIL, I tell you.
With that in mind I have tons of riccia I would happily send you for nothing. A baggie and a 79 cent stamp are not worth the hassle of any payment process. PM me your mailing address and it will be on its way. Probably with some other stuff--not sure if it is java or not as I lose track of plant identities almost instantly, but there will be some other interesting clippings. And duckweed. I come by my loathing of the stuff honestly.
:rofl: great description! (free bump)
