# Dwarf Water Lettuce?



## ByronH (Mar 4, 2010)

Does anyone know the scientific name of this plant, or if it is the same as the "normal" _Pistia stratiotes_?

I have searched online but can find no reference to the "dwarf" form being the same or a distinct species scientifically. There are mentions of "dwarf water lettuce" which bears a resemblance (to me anyway) to Salvinia, and I now have some in one of my tanks. The store said it was the regular plant and would grow into that, but online there seems to be suggestions that it remains "dwarf." But no where can I track down a valid name.

The Plant List [here: http://www.theplantlist.org/tpl/search?q=Pistia ] has a number of synonyms for this species, but there is no description of any of these. I am assuming the "dwarf" would be the same genus, but that may not be.

Byron.


----------



## miremonster (Mar 26, 2006)

Hello Byron,
I believe that there are different Pistia stratiotes variants in culture:
http://www.aquaticplantcentral.com/forumapc/showpost.php?p=639879&postcount=4
http://www.aquaticplantcentral.com/forumapc/plant-id/85503-what-plant-please.html
but their existence should be tested by targeted culture experiments and documenting.
If a taxon has synonyms, it doesn't mean that the plants originally labeled with the later synonymized names are distinguishable from each other, and that their original descriptions are suitable for distinction. Perhaps the original publications can be found by tropicos.org, botanicus.org etc.

Even if there are differences between plants under the same culture conditions, it may be that a taxonomic distinction doesn't make sense because the characters aren't stable. Especially Pistia stratiotes varies greatly depending on the growth conditions, also within the same population, so it's hardly possible to tell if differences between the plants in the nature are caused by genetic differences or by environment only.

There's really dwarfish Pistia stratiotes in tanks (as in Planted Tank's pic), but the same plants get much bigger under favorable conditions. I believe that not all Pistia stratiotes strains are able to develop such very small plants, but - see above.

-Heiko


----------



## ByronH (Mar 4, 2010)

Heiko, thank you very much for that information. I will research further with those links and the suggested sites. Much appreciated.

Byron.


----------



## miremonster (Mar 26, 2006)

p.s.
There's a paper from Schleiden, 1838, about Pistia, in German; he distinguishes a number of species on the basis of some in his opinion stable characters:
http://www.biodiversitylibrary.org/page/14899585#page/18/mode/1up
but apparently the later author(s) who synonymised them couldn't confirm that distinction.


----------

