- Wed Jul 30, 2014 1:06 pm
I haven't researched this at all so most of this is just guessing, but I would think that it's due to them being in virtually the same conditions. I've observed that some Drosera flowers seem to open differently depending on either light or temperature. On cloudy days, the flowers may not open completely. On sunny days, the flowers will fully open and for a longer period of time. Also, the flowers open earlier in summer than in winter (a factor of photoperiod?.
Anyway, I think that the flowers opening is triggered by light or temperature. So if several plants are in virtually the same conditions, they may be exposed to an identical amount of light and heat at the same time, thus stimulating simultaneous flower opening.