Mendelian

I another post, I pondered on the variation you can find in some wildflowers, including red campion. In contrast, I’ve always been intrigued by the uniformity of the valerian plant (Centranthus ruber). This common plant of wayside and cliffs always flowers in one of three defined colours – rose pink, white, or pinky-red, wherever you see it.

The example above is a colony on the red cliffs in Seaton, Devon, where all three colours are growing together. The pink is the commonest, followed by red and white. (Apologies for the poor photo – my phone was about to die and I grabbed it too fast!)

I’ve searched for an explanation of the genetics involved, but there seems to be nothing online. Remembering (from the distant past) my O level biology and the green and yellow peas grown by Gregor Mendel, I initially thought that perhaps homozygous plants are either red or white, and heterozygous ones are pink. But from my observations, far more than half are pink, and red is more common than white (despite the proportions in my phot)4o, so there’s obviously something else going on here too.

Oh well, it’s time for dinner, so my pondering will have to wait!