Thank you all. NoodleCats got me. I was asking about the Pearl weed.
I have been able to keep all other plants clean by manually removing occasional green thread algae growing with/on them, however, the pearl weed is so slender that it got entangled with the thread algae, which I am unable to remove without breaking the pearl weed. I hesitate to cut and throw some of the pearl weed since I only have a small bunch.
I have one off topic question - how do you distinguish Saggitarria subulata from Helanthium tenellus? I have both plants growing in the same aquarium and while being completely different species they look nearly identical.
There are different species of pygmy swords the two most common are broad leaf (Echinodorus quadricostatus) and narrow (Echinodorus tenellus). Sadly I think I have Echinodorus quadricostatus since the leaves are nearly the same width as dwarf sag.
Pygmy Chain sword grow in a wide range of pH. Optimum pH for growth is between 6.5-7.5 but it favors neutral pH a lot. Optimum temperature between 68-84 F.
What are the differences between pygmy chain sword vs dwarf sag?
Dwarf sag is also called dwarf Sagittaria. Most of the time this plant may also get confused with the pygmy chain sword thinking both plants are the same.
No, It is not true.
Dwarf Sagittaria has a white bottom with lots of white color roots where it can not be seen in Pygmy plants.
And also it has horizontal lines on the leaves from bottom to top where you can not see horizontal lines in the narrow leaf chain sword.
Both these plants are well suited for your foreground of the tank.
These Sagittaria differ by overall color and size. There it has light darker green and pygmy chain sword with a dark green hue.
So I think you may have got the point.! Now you have the knowledge to identify Pygmy chain sword from the dwarf sword and dwarf sag.
I had e.quad (I think) & it was much more of a crowned plant, slightly wider leaves but not the chaining habit of others. More of offsets close to the "parent" plant base. Chain swords for me tend to 3-4 leaves, a 1 inch rhizome (chain) to the next plantlet & on & on. Green leaves & sparse roots.
IME if I plant dwarf sag at the front of a tank it grows 4-6 inches. If I plant it mid-ground (higher light?) it stays short. ~2 inches. I agree dwarf sags tend toward more whitish bases. But they can do runners +/or a bushier habit. I agree the leaf patterns can be different but I don't remember what they are right now.