Quote Originally Posted by OrchidAddict View Post
Hmmm...very interesting. I noticed that the yellowing one in your photos is an "alba" variety. Do you happen to know if it's just the "alba" variations that are missing the red pigment? It would sort of make sense, as in the human and animal world there is a condition called albinism, which is characterized by the lack of any color pigment in the body. These people's skin, hair, etc, appears white. (Many people call them "albinos," but this is an offensive term to them...I'm just using it here to make sure you know what condition I'm referring to.)

Anyway, "Alba" means "white," so it would make sense that the "alba" varieties of plants would be missing pigment, just like people and animals with "albinism" are missing pigment. It would be a pretty neat discovery if we learned that we only need to worry about bleaching on "alba" varieties of orchids, and we can use the "red leaves are bad" rule for everything else. Just curious.

Thoughts? Anyone?
Yes in this case it is the alba version that miss pigments, the flower is pure white and has no fragrance.

There are many different kinds of Anthocyanins and it is not only alba versions that does miss the visible "red spots" on leafs in high light. For example my Cattleya forbesii does not produce "red spots" but are bleached, while my Cattleya guttata clearly shows "red spots" at high light conditions.

/M