Why are there roots growing from the middle of anacharis branches?

It's a characteristic of the plant. Happens all the time. They are as much a floating plant as an in substrate plant.
Len

actually NJ - they aren't really roots - but new shoots of the plant. And as Len said - that is just typical of Anachris

This big clump of plants at the top middle of the tank:



were about 1/3 the size when I put them in. Anachris will throw out lots of new shoots and can grow rapidly. Most of mine had multiple new shoots - and some grew an inch or two a day

These had grwon at least 50% larger than you see in the pic from 2 weeks ago above - so I just cut a ton of these out - back to its original size. I put them in there initially to help adsorb nutrients while my tank settled in. Now I have added a bunch more live plants - so I am slowly eliminating my anachris. once some of my other plants grow in, I will likely get rid of it all together

Well, its best to snap off what you don't want from the bottom and keep the top - they will look better that way. but for my purposes, I have sometimes kept the bottoms (easier to get rid of the excess on top for me)

Sounds normal to me. My anacharis has roots growing from the middle of the stem. These roots (white threads) eventually found their way to the substrate and pulled the stem over so it now runs horizontally along the back of the tank. This stem has now sprouted several branches which are growing vertically up from the original stem.

O