The discussion of "black" rebloomers reminded me of Dr. Peter Werckmeister's
genetic model. He described the pigment as being concentrated in the
epidermis, with brown-black the result of a combination of intense violet cell
sap and yellow plastids in the cell wall. It seems to me that there is also an
approach to black from the violet side that doesn't include the yellow. I've
looked at enough TB petals under a magnifying glass to say this makes a lot of
sense -- but wonder if this model is still accepted or if there are exceptions
even in the TBs. Has anyone done cross-sections to see whether the color is
really confined in this manner?
It is certainly a different story with the arilbreds. The magnifying glass
reveals that the pigment is not confined to the epidermis, but is actually in
layers so that different colors are seen from different angles. This means that
a fall may look like black onyx when viewed straight on but ruby-red when seen
from the side. The top layer often looks like crystalline beads -- sometimes
colorless, sometimes golden, sometimes copper, sometimes violet. Jet? Well, I
can dream, can't I?
This makes breeding for black arilbreds a REAL challenge. What about other
types of iris?
Sharon McAllister (email@example.com)