# Blyxa sp vietnam, or is it a Vallisneria species?



## HeyPK (Jan 23, 2004)

The Emerald Lake website has two very similar plants: I wonder how similar they are. 















Vallisneria triptera.................................................................Blyxa vietii (Blyxa sp vietnam)

Here is a picture from a Dutch website showing what is labeled Blyxa sp. veitnam. I had a plant that looked just like that but it had runners that looked exactly like Vallisneria runners. My plant is indicated with the yellow arrow. I wondered about that at the time. Are there any other Blyxa species that have runners? Could this Blyxa sp. vietnam actually be a Vallisneria species, perhaps not triptera, but related?


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## SOLOMON (Sep 24, 2006)

this is Vallisneria triptera http://www.aquagreen.com.au/plant_data/Vallisneria_triptera.html

There is also Maidenia rubra which has been renamed Vallisneria rubra. http://www.aquagreen.com.au/plant_data/Maidenia_rubra.html



Dave said:


> I think Val is a good name for rubra as it has the same flowers and spreads by runners. It is an annual. Quite a few years ago I collected some Vallisneria triptera from the Kimberley. I put it in some soil from the Adelaide River and had m.rubra come up among with the val. A plant appreared that I now beleive to be a hybrid. It is like rubra but has broader leaves. I had been keeping it under the name Adelaide River m.rubra. Surry Jacobs suggested it may be a hybrid. He told me back then that maidenia was very close to val.


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## HeyPK (Jan 23, 2004)

very interesting, SOLOMON. There must be some kind of gap in characteristics that separates genus Vallisneria from genus Blyxa. Maybe Cavan can tell me what it is. I'm betting that Blyxa sp. vietnam is on the Vallisneria side of the gap. I looked over the Aquagreen site last night, and I remember thinking that Madenia looked like a neat plant, and I wondered where this genus, Madinia, came from. 

Do you know if these Australian annuals are really annuals in the aquarium, that is, they die even if you regulate the daylength and keep them in good growing conditions?


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## SOLOMON (Sep 24, 2006)

Some of the best looking plants die when you look at them weird :mad2:. Dave has real trouble keeping V. triptera alive in his ponds, he has to collect it from the wild each year. I havnt had the chance to try the majority of the annuals, I really don't have enough 'tech' to keep them alive 

Dave may be getting an export license/permit soon, he did mention someone from the government coming out and inspecting his facilities. Then you might be able to compare much easier.


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## miremonster (Mar 26, 2006)

"Blyxa vietii" = Blyxa cf. vietii = Blyxa sp. "Vietnam" is IDed now.

Article in the new Aqua Planta issue, in German:
Kasselmann, C. & Petersen, G. (2014): Nechamandra alternifolia (Roxburgh ex Wight) Thwaites subsp. angustifolia Kasselmann & G. Petersen, subsp. nov. (Hydrocharitaceae). - Aqua Planta 3/2014: 84-92.

The genus Nechamandra contains only one species, N. alternifolia. The new subspecies Nechamandra alternifolia subsp. angustifolia is described by Kasselmann & Petersen, and the aquarium plant known as "Blyxa vietii" belongs to that. 
Gitte Petersen (Copenhagen) sequenced DNA, and the rbcL sequences of the aquarium plant are identical to those of a plant collected by Christel Kasselmann in Northern Thailand.

If the "Blyxa sp. India" is really Nechamandra alternifolia (and it seems very likely, is it positively IDed in the meanwhile?):
http://www.aquaticplantcentral.com/forumapc/new-plants-planted-aquariums/75042-blxya-sp-india.html
that plant belongs to the subspecies alternifolia. Occurring in India and adjacent countries, to Myanmar in the East.
The newly described subspecies angustifolia has a more eastern distribution, Myanmar to South China and North Thailand (and North Vietnam?). Differs from subsp. alternifolia by much narrower leaves.

It turns out that Paul assumed correctly: the plant introduced as "Blyxa vietii" is on the Vallisneria side of the "Blyxa - Vallisneria gap". Because Nechamandra is the sister group of Vallisneria, Blyxa is more distantly related within the family Hydrocharitaceae.

[edit] There's also true _Blyxa vietii_, known from Dak Lak province in South Vietnam only. I've no idea if that species, really a Blyxa, is cultivated.
http://www.iucnredlist.org/details/194026/0


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