# Ludwigia glandulosa ID



## Yo-han (Oct 15, 2010)

In the lfs I work we always receive the next plant as perennis. When we order glandulosa at Tropica, we receive the same plant (opposite leaved) and read some discussion here so I assume the first is glandulosa:



















This time when ordering glandulosa we receive this plant, almost Althernathera/Persicaria like leaves:



















Is this a Ludwigia? And if so, which species?


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## Cavan Allen (Jul 22, 2004)

The first is definitely not _L. glandulosa_. I can't say what it is though. _L. perennis_ is an Asian species that somehow got confused with the former.

The second, alternate-leaved plant does look like _L. glandulosa_.


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## Yo-han (Oct 15, 2010)

Thanks! I places both submersed, I'll add pictures when they're converted.


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## miremonster (Mar 26, 2006)

Yo-han said:


> When we order glandulosa at Tropica, we receive the same plant (opposite leaved)


Odd. As far as I've seen Tropica plants labeled as glandulosa, they were the true species (alternate lanceolate leaves).
I suspect that Your 1st plant is the Ludwigia "Rubin" aka "Weinrot" http://www.aquaticplantcentral.com/forumapc/plantfinder/details.php?id=218. It may have opposite as well as alternate leaves on the same stem. I've often seen that plant in LFS with the label L. glandulosa or L. glandiosa, but not yet as L. perennis. But the true glandulosa is often labeled "Ludwigia perennis", as Cavan mentions; and to make the confusion perfect, also as Ludwigia glandulosa "perennis" 

Beside that, I wonder if the true Ludwigia perennis from Asia would be suitable as aquarium plant.


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## Yo-han (Oct 15, 2010)

Here you can find a picture of the Tropica glandulosa. It's leaves are neither like the first nor the second plant I own. So I don't think I've the same plant.

About the first, I compared it with the real L. repens 'Rubin' and it is definitely not the rubin.


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## miremonster (Mar 26, 2006)

Yo-han said:


> Here you can find a picture of the Tropica glandulosa. It's leaves are neither like the first nor the second plant I own. So I don't think I've the same plant.


 The shoots of Your 2nd plant are apparently emersed, and I mean Cavan is right. The leaf form changes much in mature emersed L. glandulosa. See the last pic here, a fruiting stem, grown in the summer: http://www.flowgrow.de/db/wasserpflanzen/ludwigia-glandulosa
That plant was L. glandulosa from the trade, the emersed creeping shoots grown during the winter in a greenhouse (Botanical Garden Göttingen) had a similar leaf form as submerged ones.
See also http://plants.usda.gov/java/largeImage?imageID=lugl_001_avd.tif



Yo-han said:


> About the first, I compared it with the real L. repens 'Rubin' and it is definitely not the rubin.


OK; were they grown under the same conditions? How did they differ?


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## Yo-han (Oct 15, 2010)

Both plants are emersed. Off course the ones received by Tropica are grown under different circumstances, so perhaps they are, but mine is more red on the underside and has clearly longer, more narrow leaves.

About the rubin. Mine has larger leaves and all leaves are opposite, something I've never seen on Rubin... But perhaps this can be contributed to the difference in circumstances as well.


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## miremonster (Mar 26, 2006)

Cavan Allen said:


> _L. perennis_ is an Asian species that somehow got confused with the former.


I'm reading Kasselmann's article "Eine neue Aquarienpflanze: Ludwigia glandulosa WALTER (Onagraceae)", Aqua Planta 2-1991, 62-65. According to that, the glandulosa first appeared with the label "Ludwigia perennis" at the end of the 80's in LFS (in Europe), distributed by Tropica. In 1989 a short portrait of the plant, also as "perennis", was published by C. Christensen. C. Kasselmann sent herbarium material with flowers and fruits to Missouri Botanical Garden where it was determined by Dr. C. Peng as L. glandulosa subsp. glandulosa.


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## Yo-han (Oct 15, 2010)

The second turns out to be Glandulosa indeed. The first I still have no clue. It didn't turned as red as Rubin, and only had opposite leaves submersed. The leaves where larger than repens and it didn't make any side-shoots which my repens does quite often.


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