# Please help me ID this plant



## rafael.nicolaidis (Dec 23, 2021)

It was collected from river Tainhas (28° 48′ 42.8″ S, 50° 36′ 15.49″ W), in the upstream rapids. 
Water was cold and clear (don´t know the exact temperature, pH and hardness, unfortunately, but according to some governmental documents it´s pH range is 6.4 to 6.9 and very low to undetectable N and P). There was some sediment in the exact spot of collection, but most of the substrate is a bedrock composed of basalt stones.

It was found in a shallow area with less flow, together with what I believe was some type of _Isoetes _(this other plant didn´t survive the trip home). 

I have planted it in my tank, and it seems healthy but doesn´t thrive. It is a non-CO2 injected softwater tank.
I suspect it my be amphibious, as it was in a shallow area and the volume of water in that river system is variable, but at the moment of collection there was no emergent growth.


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## mistergreen (Mar 3, 2007)

Tough one. If you can go back to find the flowers of this species, it would help.


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## rafael.nicolaidis (Dec 23, 2021)

mistergreen said:


> Tough one. If you can go back to find the flowers of this species, it would help.


I am thinking some type of _Sagittaria._


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## mistergreen (Mar 3, 2007)

rafael.nicolaidis said:


> I am thinking some type of _Sagittaria._


Yeah, that’s what I thought at first but none Is native to Brazil unless it’s invasive. Can you lift it up so we can see the bulb and roots? I think there’s one that looks like a green onion, Crinum thaianum


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## rafael.nicolaidis (Dec 23, 2021)

Actually there are a number of species of the genus _Sagittaria _that are native and common to Brazil.
I believe I have the ID.

It is, probably, _Sagittaria montevidensis_ in its immersed form.









_Emersed growth of Sagittaria montevidensis - _this is what we usually see

Found this picture of the same plant in its immersed form:









So I am guessing it is not thriving because in nature it really seeks to grow emergent.


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