Anthocyanins - a group of chemicals responsible for the colouring
of many (all?) of the red and purple shades found in plant material.
Sunlight intensifies the colouring (eg: the ripening of tomatoes
and apples, Sarracenias, etc.)
I would guess your "all green plants" were either young or shaded.
The problem with Dionaea (well, one of them anyway,) is the wide
profusion of supposed 'forms' which on closer examination prove
to be inconstant habits. The redness of an individual VFT plant
depends on genetic factors governing anthocyanin production, the
environmental conditions prevailing on the plant as it grows, and
to a lesser extent (so it seems from my own observations and as
has been noted before by other growers,) can vary from year to year.
Growth habits likewise do not remain consistant - supposedly
'prostrate' or 'erect' types can (and do,) spontaneously change
their habit in response to environmental or other factors.
Having said all that (and you think I'm a killjoy lumper, right? :)
there are some true forms that *do* hold consistent characteristics -
The only one I have seen with my own eyes is the "red clone" which
I assume Fernando refers to. This is a gorgeous plant - under good
light, there is *no* green on the plant. It is burgundy from the
ground up - petioles, trap surfaces (inside and out,) bristles, hinge,
the lot. I have reliably heard of - "green clone" (an anthocyanin-
free form,) "dentate" (with the trap fringe reduced to 1mm saw-
tooths,) "fused-tooth" (which I can only imagine!) "cup-trap" (?) and
"variegated" (presumably something like the "Royal Red" now being
marketed from Australia?)
Certainly the red-clone, and I can only assume the others as well,
do not come true from seed because they are extremely rare (perhaps
unique,) mutations which will almost certainly be lost if genetic
remixing via sexual reproduction occurs. AFAIK seed will revert to
type virtually as often as seed from "normal" plants even if you self
it. That's why it's called "red *clone*" - it needs to be reproduced
asexually.
And before anyone asks - No, I'm afraid I don't know where to get
any of these forms, though I'd be interested myself if anyone does
know. "Royal Red" has been advertised in the latest CPN, but
wholesale only. BTW, does anyone know how the fuss surrounding
the patent application for that worked out? - I remember there was
a lot of dispute last year, but I don't think it was followed up
after the objections had been considered (and presumably rejected
given the CPN ad,) by the relevant Australian authorities.
Hope this helps,
Peter