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Re: pygmy swords

Roger S. Miller asked....

>A couple years ago I bought a few (5, I think) plants that the local store
>called "pygmy chain swords".  I assumed that the plant was E. tenellus and
>the fish store guy agreed.  (He might have agreed if I thought they were
>Martian snoot grass.)  The plants were apparently in an emersed-grown
>form. They were about 2 1/2 inches high and their leaves were straight and
>consisted of an indistinct petiole and a lanceolate blade.  The blades
>were only about 4 millimeters across and slightly shorter than the
>petiole.

This is a pretty good description of E. latifolius. There are
probably several varieties. Page 154 of Aquarium Plants by Rataj
and Horeman has a good picture of the emersed form. It depends on
what you mean by "indistinct petiole."

>Their new submersed-grown leaves were strap-like, recurved and initially
>about as long as the original leaves - 2 to 3 inches - with a small but
>distinct midrib running the length of each leaf. Once the first plants got
>established they started sending runners out and spread very rapidly. At
>the same time, the plants started putting on longer leaves and soon they
>got over 10 inches long and reached the water surface in a 20 gallon
>"long" tank.
>
>At that point I decided they weren't very "pygmy" and gave away most of
>the batch.  The ones I didn't give away got stuck into a low light tank
>with no CO2 where they promptly wasted away.  I got a couple out before
>they disappeared completely and now have colonies of these plants in a
>couple other tanks.
>
>But I don't know what they are.  I concluded that they got too big to be
>E. tenellus.  Looking for other possible identities I came up with
>Sagittaria subulata, E. quadricostata, E. latifolius and E. angustifolius.  
>As near as I can tell there is no easy distinction between these plants.  
>Does anyone know how to tell them apart, or have any suggestion what mine
>might be?

I may have the same or a similar plant and had the same ID problem.
The leaves sometimes grow to 12 inches for some reason, but almost
always stay short. When a plant sends up a flower stalk, you will
be able to tell if it is a swordplant. Swords have bisexual flowers,
sagittaria will have male and female flowers on the same floral stalk.
In my tank the flower stalk grew from one of the tall specimens.
The 10 to 12 mm flowers consisted of three white petals with a
yellow center.

This is a very useful and versatile plant. In your case Echinodorus
isthmicus might be an even better bet. Baensch II Atlas describes
it as "single veined."

>In addition to the details above, I can add that the plant when grown
>under fairly dim light tends to stay small, with leaves no wider than 3 or
>4 mm wide and about 3 inches long.  Under brighter light they grow longer
>leaves and under some conditions the leaves also get up to 6 or 7 mm wide.
>
>
>Roger Miller

--
Dave Whittaker
Gloucester, Ontario
Canada
ac554 at FreeNet_Carleton.ca