Riccia Growing More With Lights Off? :s

[guppy_man]

I'm now a poor university student and have had afew student nights out this week spending the small amount of cash i had.
I went out tuesday night after turning my tank lights off, stayed over a mates for the night, then went to london wednesday morning, came home very late wednesday went straight to bed, forgot to turn the lights on this morning, and only now just turned them on. I have noticed my riccia has grown so much that it is separating from the main piece and trying to float to the top.

The pic in my sig is from monday, the riccia on the right has grown a quarter of the way up the tank within around 2 days without any light, but Co2 still running.

Why is this?

 

[aaronnorth]

plant can store enrgy if they have no light and use it to grow, only trouble is i cant remember what it is called

 

[guppy_man]

lol, atleast that explains my question. cheers