Why Crocus Flowers Open for the Sun
So quickly, the Snowdrops (Galanthus nivalis) have passed their peak, but I cannot be sad. Their flowers will last a while longer, and in the meantime the Crocuses are stepping up to the plate.
In my garden, these are mainly Crocus tommasinianus, or Tommy Crocuses. Tommies have a limited color range (mainly purple), but many consider them more resistant to rabbits and other evil garden vermin. Certainly, that has been my experience.
I have a strong childhood memory of a patch of Crocuses near my parents’ house. Every March I would look for them on the way to school. When they bloomed I always felt a little jolt of happiness. And so I have a soft spot for Crocuses to this day.
Anyhow, yesterday Judy went out to take pictures of the garden, including the Crocuses. It was a day of mixed clouds and sun, and I was a little anxious that Judy catch these flowers while the sun shone, as they are likely to close up when it is overcast.
Which made me wonder: why and how is it that Crocuses (and tulips and many other flowers) close up in the absence of light?
A little internet research revealed an answer, or at least a scientific name for the phenomenon: nyctinasty. Nyctinastic flowers close up in the dark either by pumping water out of cells at the base of the petals, or by growing new cells on the outside of the base of the petals, which forces them shut. To open, they grow cells on the inside.
To be honest, it’s not completely clear to me how this mechanism works, but I’m willing to believe that it does.
It’s impossible to know for certain why flowers engage in this behavior (isn’t it odd to think of flowers having behaviors?). The most popular theory is that nyctinasty evolved to protect pollen from dew or rain. Apparently wet pollen is not as attractive to pollinators and/or is not as conducive to pollination.
The other thing that I wonder about: couldn’t they come up with a better name for this phenomenon than nyctinasty? It sounds like something very unpleasant. More evidence that botanists need to hire marketing consultants to review all their naming decisions.