Why Are Some Plants Red?

[TallTree01]

Why have a few select plants evolved to be red?
Isn't it harder to photosynthesise when being not green?
I'm guessing they didn't evolve just to look spectacular in aquariums

 

[TwoTankAmin]

Read on .....
 
http/www.ucmp.berkeley.edu/glossary/gloss3/pigments.html
 
http/courses.chem.psu.edu/chem35/plantpig.pdf

 

[thefishnoob]

Theres a lot of light, i guess, so theres excess photosynthesis I believe. Here, an example: My Giant Duckweed, when bought, had pale/greenish undersides; now, after basking for a month or so under a 23 watt CFL, here is the undersides:

 
Its on the top left. Look at the red undersides!