# Mystery Plant



## s2man (Nov 8, 2016)

I bought an assortment of plants on aquabid.com. The seller had a list of species, but this buy wasn't on the list. The closest I have come, based on pictures, is PENTHORUM SEDOIDES. But that has whorled leaves. Can anyone name it?

Leaves are alternate and serrated, about 1" long including their stem. 3/4" long leaf surface.
The plant is *very* slow growing, only four new leaves in a month. The new leaves are bright green, the older ones a yellowing. Sorry about the pic; Lots of tannins as this is a new soil-planted tank.

Thanks in advance.


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## Cavan Allen (Jul 22, 2004)

That looks like emersed _Hygrophila difformis_. Not converting for some reason?

Those leaves are opposite. That only refers to how many leaves per node. What you are referring to is secondary to that.


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## s2man (Nov 8, 2016)

Thanks, Allen.

Oops, that 'alternate' was a slip. I'm not sure how I did that, but I meant to say opposite.

Edit: yep, _Hygrophila difformis_ was on the list of plants.


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## shaunwinterton (Jun 27, 2012)

Odd that it has not grown very much. Hygro difformis should grow pretty quick under most conditions. ID looks accurate, although the lack of growth makes me wonder.


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## s2man (Nov 8, 2016)

Yep, Shaun. A couple of species are just hanging in there. But most of the plants went bonkers with the high ammonia during the soil mineralization. I had to trim the fast-growning stem plants after only two weeks. 

This is what I expected with a big selection of plants. I just planted them all and figured, let's see who does well under my conditions. Though, I still wonder, what is the missing factor for those who aren't thriving?


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## s2man (Nov 8, 2016)

The plant is doing well, but has not switched to submersed foliage. It is different from this pic of emerged plants in that it my plant's individual leaves each have a bit of stem, as opposed to the pic, where they have no stem and the main stem is red:

http://www.aquaticplantcentral.com/forumapc/plantfinder/images/Acanthaceae/Hygroemersed.jpg


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## Yo-han (Oct 15, 2010)

Or highly serragated Shinnersia rivularis, but this should grow like mad as well...


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## shaunwinterton (Jun 27, 2012)

Still confident it is Hygrophila difformis (or whatever the current correct name it for it). Shinnersia has crenate leaf margins instead of serrate, so I don;t think it is that one. Flower is really different by the way, so when it does flower you'll be able to tell right away.


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## miremonster (Mar 26, 2006)

I agree, 100% Hygrophila difformis. Recently also one emersed stem that I put under water (for a photo of the submerged form) took a while before it grew further, for any reason.

Years ago a friend noticed that newly bought H. difformis hardly developed the typical divided leaves under water, they were submerged and light green, but not deeply lobed. Earlier he had typical difformis for years. Conditions about the same. We speculated that there are possibly different clones of this species around. But no idea...


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## miremonster (Mar 26, 2006)

p.s.


shaunwinterton said:


> Hygrophila difformis (or whatever the current correct name it for it)


I remember the name Synnema triflorum in older aquarium books, there's also the combination Hygrophila triflora, even used in recent sources, apparently synonymous with H. difformis etc. On The Plant List the latter 2 names are regarded as "unresolved". But at least in aquaristics H. difformis is the most used name. However, a new revision of the whole genus Hygrophila is much needed.


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## Cavan Allen (Jul 22, 2004)

I have seen the reverse, with a plant growing finely divided leaves above water! The humidity was really high. I'm not sure what the cause of this plant's growth is, though.

Yes, a revision of _Hygrophila_ is sorely needed. But I don't think one is coming.


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## s2man (Nov 8, 2016)

*Finally, new form*

At last, submerged growth. I don't understand why it took so long to convert, but I don't pretend to be an aquatic guru.









Old and new growth.









Closeup of new foliage.


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## Cavan Allen (Jul 22, 2004)

Yeah, no doubt that's _Hygrophila difformis_


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