# purple duckweed?



## Ras (Nov 7, 2013)

anyone know if this is a normal growth stage of common duckweed or if it is a different species? 
I found about 12 pieces of purple duckweed when i was thinning out the floaters, the other 99% of the duckweed was normal pale green, these were more dark green with a purple trim and it caught my eye so then when I flipped them over, deep purple bottoms. needless to say I isolated them 
























any ideas if this is a species trait?


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## NanoDave (Feb 25, 2013)

Not to sure but I've grow duckweed for a year or so now in a multitude of tanks. Up until last week I also noticed some reddish purple bottoms on a few of mine as well! You are not alone and I'll be staying tuned to know the answer as well. Needless to say I too isolated them and they will not become silver dollar food anytime soon.


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## Zapins (Jan 7, 2006)

Very odd indeed!

I am not sure why they are purple. The only thing I can think of is possibly phosphorous deficiency? In terrestrial plants that often causes plants to develop deep purple stems. If plants in the tank seem healthy and aren't losing old leaves then it probably isn't that. 

Perhaps it is normal for duckweed at some stage in its life cycle? 

I am also curious to know the reason.


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## adavisus (Oct 14, 2007)

Greater duckweed has a distinguishing feature, in well lit conditions it will have a deep purple tone on the underside of its little pads. In very fertile conditions it grows larger than the other duckweed species


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## Zapins (Jan 7, 2006)

Neat. That seems similar to red plants turning red with higher light as well.


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## peachii (Jun 1, 2013)

Agreed, it's greater duckweed. Will grow to a very nice deep purple, get longer roots similiar to salvinia, grow about 5 times the size of normal duckweed and be easier to keep under control that regular duckweed. I really like greater duckweed unlike normal duckweed which is a spawn from hell


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## Zapins (Jan 7, 2006)

peachii said:


> I really like greater duckweed unlike normal duckweed which is a spawn from hell


That and wolffia.


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## Ras (Nov 7, 2013)

sorry but I ave to disagree, I have greater duckweed to compare it with, and though people say they turn purple-red on bottom I find that to be a judgment error, to me they look deep red and always have. velvet is the closest color that comes to mind, and when i put the two plants side by side there really is no comparison 








notice the color differences, in the roots and leaf, as well as the roots on the smaller duckweed being longer than the giant duckweed . one thing i have noticed and has helped me to ID ginat duckweed other than its color is the root length. Out of all the floaters ive grown they have the shortest stubbiest roots for a plant their size. notice the "purple duckweed" has long green roots though 








and top view also makes me feel like these are completely two different things 
if you notice they have two very different leaf shapes, the smaller being elongated and the larger being more oval or round shaped, other than the size this is one thing I found very noticeable 
I _was_ entertaining the idea that they could possibly be young giant duckweed but then the issue whith why the younger smaller plants would have longer roots than 100% of the larger ones
it isnt like they are shrinking right, and nothing in my tank nibbles on them. 
then there is the fact that these purple duckweeds are multiplying and dividing before gaining the size of a normal GDW, you would expect it to gain size then divide.











these two plants above came from the same tank so you would expect all the colors and growth rates/ patterns to be similar if they were the same species
all in all I don't think it could be giant duckweed.


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## Ras (Nov 7, 2013)

update: I kept them isolated and they multiplied, every new plantlet and leaf had the same purple characteristics and so far none have grown bigger than the head of a pen or pencil
I managed to remove most the green duckweed from my tank and replace it with this purple duckweed, and i LOVE it
Im going to isolate some more soon for trading purposes, so I can have some of it that is free of any common DW 
curious what happened with yours nano dave


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## AirstoND (Jun 17, 2011)

what lightbulb setups are u guys using?


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## Ras (Nov 7, 2013)

up until a few days ago I was using 2x 4.2ft 54watt bulbs
switched to t8 shoplights because my co2 couldn't keep up with that much light, algae issues


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## aquabruce (May 10, 2012)

Landoltia punctata - spotted-duck-meal ??

or Spirodela polyrrhiza - common duck-meal ??


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