This is a discussion on My try at a new 55 within the Freshwater Journals forums, part of the Aquarium Photography category; -->
they seem to be the MTS but as stated they are very small so who knows hahaha. Still only count 10 atm....
Ohh didn't mention this before as I should have. Since hornwort likes light (and this goes for any stem plant.) you should plant each stem separately leaving an inch or so between them. That way the light can get all the way down to the bottom leaves. What happens if you plant them in bunches and you don't have bright enough lights is the lower leaves fall off leaving a bare stem while the top leaves stay green.
Since you already have them planted you can just see how it goes. If this starts to happen just give them some space between each stem. Sorry for not mentioning this before!!