# Is this submersed Lindernia dubia?



## asukawashere (Mar 11, 2009)

So. I've been going out on a lot of crazy collecting missions with hopes of eventually turning up some Lindernia dubia (on account of the fact that the USDA claims it lives here and therefore I must get some). The good news is, I finally found it (photos below).

However, I also found a... _something_ in the same area, as I'm wont to do on these field trips. I initially thought it to be a submersed form of the L. dubia (it has similarly serrated leaf edges and a similar overall texture), but getting back and looking at the photos on the plantfinder, I'm not so sure. The leaves are much more acuminate than the PF photo, for one. Also, there's the interesting fact that this was growing in a mostly shaded area - which according to plantfinder, L. dubia doesn't do. It might get a little AM sunshine from an angle, but for most of the day this part of the pond in question is overshadowed by trees reaching out over the water. These stems were growing straight up.

...I will, however, point out that I pulled my L. dubia specimen from a shady area, so I'm hazarding a guess that it can survive in the shade. The leaf shape has me really thrown, though.

So... photos are below, anyone have any idea?

First off, my L. dubia which I am very inordinately proud of:









flower!!!









the whole specimen

And, my possible submersed form oddity:









Yes? No? Maybe?

Another shot:


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## Cavan Allen (Jul 22, 2004)

Are the stems quadrangular (square)? It's hard to say for sure from the photos, but I think you probably did indeed find _L. dubia_.

The bottom plant is _Gratiola aurea_. Once highly coveted by me, it has proven to be a very difficult plant to culture. Almost a year later, I have roughly the same amount I started with. I just started over with more light and a setup with which I'm more comfortable, so I'm keeping my fingers crossed. If you do try it, emersed stems will probably work better. On emersed specimens, look for flowers with a bright yellow corolla.


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## HeyPK (Jan 23, 2004)

I am pretty sure that _L. dubia_ is what you have. It is common in ditches here in central Mississippi. Here is a picture I took of it









I got it growing submersed, and it had rounded leaves, not like the pointed leaves of your #2 plant.

http://www.aquaticplantcentral.com/forumapc/aquarium-pictures
[IMG]http://www.aquaticplantcentral.com/forumapc/aquarium-pictures/displayimage.php?imageid=5715&original=1


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## asukawashere (Mar 11, 2009)

@Cavan - yes, the stems are square. Thanks for the ID confirmation, I'll be excited to try growing this Lindernia in some of my setups. At least, after it gets a chance to grow out more in emersed settings.

Also, thanks a bunch for the ID on the Gratiola. If it's that hard to grow, perhaps I'll bring some of the stems I found to my next plant club meeting and split them between a few people. Possibly someone will have the right conditions for making it take off. For now, though, I stuck it in my 55gal warm-water with 4x24w 6700k T5's and 2 DIY CO2 bottles. Do you think it'll do okay there? Or should I move it to my better-lit 20g guppy tank?
I'd be interested to know what conditions you feel are appropriate for keeping it. 


@HeyPK - thanks for the extra conf. on L. dubia. Your specimen looks much nicer than mine!  Did you do anything in particular to convert it to submersed growth in that little dish? Looks like it would be great in a scape, if you had enough for a big midground thicket.


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## HeyPK (Jan 23, 2004)

> ----did you do anything in particular to convert it to submersed growth in that little dish? Looks like it would be great in a scape, if you had enough for a big midground thicket.


I floated the stem in a guppy tank for three to four weeks until it had produced some submersed growth and looked like this (the plant on the left):









When grown submersed, it tended to grow straight up without any tendency to branch. Its internodes were rather long; perhaps it needed more light.


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## Cavan Allen (Jul 22, 2004)

_L. dubia_ is quite an attractive plant if conditions are right. Lots of light, iron, etc. It will still grow with less, but leggier and without teeth on the leaves. Easy to grow, but not quite as easy to grow at its best.

I imagine the _G. aurea_ would do best in nutrient poor, acidic conditions with strong illumination. I'm just not sure.


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## asukawashere (Mar 11, 2009)

Well, I went back to the mudhole I got both from this morning, just to confirm it gets some AM illumination. It does, but the_ L. dubia_ still managed to be in the shadiest part of the bank. Go figure.

In any case, I don't know if this helps you at all, Cavan, but the _Gratiola_ was growing in 12-18" of water with muddy substrate along the shadier side of the pond, in between specimens of _Vallisneria americana_, _Eleocharis spp._, and the occasional bush of some kind of _Potamogeton_. There was a patch of _Elatine americana_ not far away, but it didn't seem to overlap mcuh with the Gratiola. Temp-wise, the water probably reaches the low 80s in the sunny parts of the surface, and, this time of year, up to somewhere in the 70's in the shade/deeper down.

I'll bring some of both of these plants to my plant club and see how they fare for everyone. 

HeyPK, thanks for the tips. I'll probably try something similar with the guppy tank and whatnot.


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## HeyPK (Jan 23, 2004)

It doesn't have to be guppies!  What is important is that it is floating at the surface where it gets a lot of light. CO2, iron, and other nutrients, including micronutrients are also important. These conditions help the transition from emersed to submersed. The plant will do a lot better than it will if planted in the substrate at the start.


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## asukawashere (Mar 11, 2009)

HeyPK said:


> It doesn't have to be guppies!  What is important is that it is floating at the surface where it gets a lot of light. CO2, iron, and other nutrients, including micronutrients are also important. These conditions help the transition from emersed to submersed. The plant will do a lot better than it will if planted in the substrate at the start.


LOL, I figured as much. It just happens that my guppy tank has higher lighting than most of my other tanks and plenty of ferts (and DIY CO2, which is the only kind of CO2 I use).

The other thing I'm thinking is of planting it semi-emergent in one of my trays to get it a little bigger before I start trimming off bits to put in the tank, but getting used to at least swampy conditions at the same time. I'd let the tips stick out to get it all the CO2 it needs, but I figure the roots and lower stems would at least be less shocked if I then stuck it underwater


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