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Re: Heteranthera dubia

On Tue, 25 Jan 2000, Michael Grace wrote:

> I picked up this plant at a local auction last weekend, but can't find any
> relevant info in the archives, thekrib, Tropica, or by web search.  I would
> like to know its requirements:
> Lighting?
> Water conditions?
> Growth rate (fast/slow)?

Heteranthera dubia is a North American native related to Heteranthera
zosterifolia (star grass), which is kept more commonly.  It's described by
Rataj and Horeman, who don't think it's very decorative.

Last August I saw some plants growing in the Concho River near San Angelo,
Texas that I subsequently described to this list and asked if anyone could
ID it.  A reader replied that it sounded like Heteranthera dubia.  After
reading some descriptions I think he was right.

The plant I saw grew in shallow water in full sun.  It was rooted in a
coarse gravel substrate, spread out on the water surface in thick mats and
sent very pretty, single bright yellow flowers up on stalks above the

The water in the Concho River at San Angelo in August is not very
fresh.  I didn't measure pH or hardness, but from the limestone gravel,
clam shells, locally opaque green water and the calcite cement holding
everything together I'd guess the pH was around 8 in the morning and rises
to 9 or more in the afternoon.

I haven't grown it in an aquarium, but judging from it's presence in the
Concho, you don't have to worry about hard water, and CO2 is probably
optional as long as the light is bright.  Otherwise I expect it would be
much like H. zosterifolia, which grows like a weed with CO2 in moderate
or bright light.

How it responds initially in your tank may depend on the conditions that
it was grown under before you got it.

Roger Miller