A question for orchid experts
Why did many have yellow pollinia?
Hello Mark,
that's a difficult question. Discussing the genetic properties of such a complex species is a real challenge.
In general D.m. tends to be of paler color on wetter and more acidic soil than in dryer and less acidic conditions.
Sometimes the ground color may be white but what I observed is that if the pollinia are yellow, the ground color of the flowers is ALWAYS white. This does not necessarily have influence on the markings of the flower. Quite often in this case, the markings are rather pale (as shown in your photos) but there are also plants with quite deep colored markings (an extreme example for this can be seen here:
http://sfo-normandie.fr/photos/dmaculata_hyperc1.jpg). These are especially beautiful because the flowers are 3-colored and of good contrast - making a very vivid display. All real D.m.-albinos too have yellow pollinia.
I think that the yellow pollinia (yielding also the white ground color) is caused by a simple recessive gene although there are other genetical dispositions that may also cause the flowers having white ground color (but not together with yellow pollinia).
Maybe I can tell you more in about 2 years....
