Here is an informative article about it.
https://www.aquariumdomain.com/adSocial/index.php/kleiner-bar-sword/
Info is a bit inconsistent because its an old hang around in the trade since 1995.. Nobody seems to know its true origine. Some say its a cross breed hybrid other say it originated in a lab as result of an genetic experiment. The only one who realy knows is its Daddy.
http://www.seerosen-hoechstetter.de/php/index.php
I never grew this plant very long in its submersed form and it loves to grow emersed. It actualy happend unintentionaly, This sword is a remarkable relative undemanding plant. It able to detect its invironment and that i find very special and intriguing. Since both forms are completely different but it will always search for the surface and once a submersed form leaf reaches this surface it will grow its leaftip over the waterline. There it starts to dry out rather soon. If this leaf is left on the plant others will follow, this seems to be the trigger for the plant to know where its at and it starts growing out different emersed form small leaves on long stalks. Once this new form leaf makes contact with the atmosphere it starts to grow bigger and the intire plant stops making submersed form leaves. It switches completely into a different mode and flowers vigorously all year long.
Don't let the name fool you "Small Bear". because it can grow up to 50cm - 20" submersed and over 80cm _ 30" emersed.. Kleiner Bär alias Jungle Star probably was named by its father after the star constelation "little dipper" which translates as Kleiner Bär in German.
But this is just a best guess.. Because it aint small, but likely back than still one of the smallest swords available.
Anyway, this remarkable mind boggling build in detection system, makes it a rather versatile plant with Big and also Small potential. The plant regulates its size in the depth it is planted in
As said it geneticaly reaches for the surface and it will keep growing till it gets there and it will size it's submersed and emersed form leaves up to the planting depth. If planted very shallow it will stay a rather small plant.. As you can see in the picture
@dw1305 posted above, that Kleiner Bar was planted 25cm -10" deep, than it grows 10" submersed form leaves reaching for the atmosphere. To maintain this size you need to trim of submersed form leaves that pop the surface sniffing the atmosphere. And as reported if planted 20" deep it can grow 20" tall submersed form leaves. But if planted very shallow in 2" depth it reaches the atmosphere rather soon and it has no need to grow very much bigger.
This Kleiner Bear grows in my garden tub planted 2" deep standing in the full sun all day long and it stays about this size barely 4" to 5" tall, it has reached its goal no need to grow bigger.
This young one is also planted outdoor 2" deep, still submersed gathering strenght, it was a about leafless rhizome 2 months ago. Planted this shallow it probaly alreadt gets enough CO² it doesn't bother making submersed form leaves.
If your goal is small staying Echinodorus.. Take a look at the cultivar - E. Regine Hildebrandt, no idea if it already found its way to the United States.
https://www.flowgrow.de/db/aquaticplants/echinodorus-regine-hildebrandt
I'm also growing a few of this one emersed at the time, yet have no submersed form experience with it, but reportedly its one of the smallest available.
But they are simply very stunning addaptable plants.. A plant sp. that showed me there is more to plant life than meets the eye..