Re: wide leaf chain swords

>From: KB Koh <KB_Koh at ccm_ipn.intel.com>

>I'm sure it is E.Quadricostatus as the leaves are between 10mm-15mm wide. Or 
>could it be a new variety of E.Quad?

When I questioned if is is E.quadricostatus, I probably used the term too
loosely. Several different wide leaf swords have been described, and as I
indicate, the same plant will take on different size depending on the
conditions.  Rataj, in his 1967 Revision to the genus, mentions 4 wide-leaf

                        length(cm)      width (cm)
E.latifolius		10-25 	          10-15	

E.quadricostatus 	10-15	          10-20		
   var. xinguensis	
E. austroamericanus	1.5-5 	           5-10

E. angustifolius	30-50 	            5-8

In their 1994 monograph on Echinodorus, Robert Haynes and Lauritz
Holm-Nielsen use a single species (E. bolivianis) to describe all of the
wide leaf varieties.  They suggest this should replace the names
quadricostatus and other species or geographic variations of the wide leaf
chains. (including their older synonyms:  Echinodorus intermediatus, E.
magdalenensis, E. grisbachii). I beleive there are plants that are
distinctly different in appearance and growing behavior and prefer to use
different names to keep my plants apart. 

>remember someone mentioned that they will grow tall in low light.

I have mentioned that E. tenellus var tenellus (pygmy chain sword) grows
taller (for me!) with less light. I find the largest plants in the back
corners of the tank.

> Is this true 
>or just true if you have CO2 injection.

I don't know. I haven't tried CO2 and dim light, as I already indicated.

Controlling the height of the sword plants is still a mystery to me.

 - Besides the effects of CO2, light intensity and nutrition, the lighting
period is also said to be important. I have not yet experimented with this,
but Muhlberg says in short-day conditions, the leaves have different shape
(more pronounced stem). He also says the leaves are less long for some
chainsword species.

 - I forgot to mention that I even have different sizes of what I call
quadricostatus in one tank that has a mix of chain swords. I suppose
allelochemicals may be a factor in this case, and to properly study these
plants, it may be important to keep them separated from other plants.

I hope this gives you some ideas on what to try. Let us know what happens.

Visit the Aquatic Gardeners Association home page
 at <http://blake.oit.unc.edu/~fish/aga/>