# not potamogeton?



## kingearwig (Dec 14, 2008)

I am pretty sure this is not potamogeton illinoensis. I found it in a shallow ditch here in indiana. I tried to get a good pic of the veining which seems to contraindicate potamogeton. Also has rounded ends... Any thoughts?


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## miremonster (Mar 26, 2006)

I'm sure it's a Potamogeton, don't see any detail that contraindicates this genus. The species is another question...


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## Zapins (Jul 28, 2004)

I agree it looks like a Potamogeton to me too. The veins on it aren't unusual. Many other Potamogetons have that pattern, like Potamogeton crispus for example.


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## Lakeplants (Feb 21, 2011)

Based on the leaf veins, blunt tip, and slightly flattened stem, I'm going with Potamogeton crispus. Look at the leaf margins under magnification to confirm; you should see small teeth. It's definitely not P. illinoensis.


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## kingearwig (Dec 14, 2008)

even without magnification I do see small teeth on the leaf margins. So Potamogeton crispus it is. I was hung up on illinoensis didn't really look into P. crispus. I thought it had a more southernly range. Thanks guys! I really like this plant. I have had it for just a couple of days and on CO2 and 50 watts of GE daylight cfls it is really taking off.


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## Lakeplants (Feb 21, 2011)

P. crispus survives well under low light conditions. Its range is throughout the U.S. - it's very common here in Wisconsin, and is considered an aquatic invasive species here. It behaves well in some lakes but becomes overabundant in others, primarily eutrophic lakes and reservoirs.


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## Zapins (Jul 28, 2004)

I'm not sure that it is crispus. I was saying that the veins in the leaves are similar to crispus but not that it is that plant. The leaves don't look undulated enough to be crispus, but who knows for certain... Potamogetons are like hygros in that there are so many variations its hard to tell one completely from another.


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## HeyPK (Jan 23, 2004)

It is a Potamogeton, and it looks very much like P. crispus. If it has fine teeth along the edges of the leaves, it probably is P. crispus.


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## miremonster (Mar 26, 2006)

I guessed P. crispus as well, but don't know if there are similar species in N America (apparently not?). If it had been collected in Germany, I would be sure with P. crispus. Here it's also an abundant water plant mainly in the more eutrophic waters. Years ago I grew it in a small tank, it developed less undulate leaves similar to them of kingearwig's plant.


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## HeyPK (Jan 23, 2004)

I have looked at a lot of pictures of American Potamogetons, but I probably have not seen them all. Maybe the other Paul, Lakeplants, could give an opinion.


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## Lakeplants (Feb 21, 2011)

Hearing that this plant was wild-collected in Indiana, there aren't many other choices. The combination of vein structure, blunt apex, serrated margins, and slightly flattened stem all point to P. crispus. The reason that the leaves are not undulating is because the plant is too young. P. crispus goes dormant in June-July in most situations, and resprouts from seeds/turions around October. The leaves will eventually develop their characteristic wavy margins and crispy texture, but not until the plant matures a little more.
Also, very few plants could be wild-collected in the Upper Midwest at this time of year. Most aquatic plants follow the opposite schedule - grow in spring and summer, go dormant (or die off) in fall.


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## kingearwig (Dec 14, 2008)

very interesting information. thanks so much,everyone!
So since I have this plant on 12+ hours of light, should I expect this plant to go dormant on me once it is mature and happy?


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## Lakeplants (Feb 21, 2011)

If anything will change, I think you'll see evidence within a few weeks. The die-off of P. crispus in early summer is stimulated by temperature, not photoperiod. You will find P. crispus growing year-round in areas with strong groundwater input, where water temperature does not fluctuate as much. In areas that get quite warm though, like shallow reservoirs, P. crispus goes dormant for the summer to avoid the high water temperatures.

What kind of substrate do you have the P. crispus growing in? Did you collect the roots as well or plant a fragment?


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## kingearwig (Dec 14, 2008)

I did harvest roots also. I have it planted in mineralized soil with sand on top.


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