My husband was once re-gifted an Oxalis of undetermined species. Hundreds of species there are. It is flourishing indoors with many sets of three large triangular leaves, undertones of burgundy, and dainty white flowers on satiny spindles. This “false shamrock” is happy as can be.
What fascinates me about the plant is how the leaves neatly collapse like parasols each evening.
As attentive as we are to the plant, I have yet to see the plant turning itself in for the night. I always arrive in the room too late, after the leaf closing is done. I imagine a thought bubble above its head “Sorry, you missed it again. This evening you were too busy stirring the chili, and last evening you were too busy taking out the garbage.”
Same routine in the morning. After each morning’s light comes in, I’d find the plant’s leaves already unfurled ready to collect rays of sun. Missed it again.
So why and how do the leaves open and close? And precisely what triggers that mechanism? I’m told the process is called photonasty, powered by changes in turgor pressure in cells at the base of the leaf. If any phytochemists out there would like to shed more light on this subject, let us know.
Since a watched kettle never boils, we were about ready to pull the tripod out of the closet and timelapse it. Lo and behold, someone’s saved us the trouble, one species viewable online. It’s a far more efficient way of seeing it happen rather than staring at a plant for an hour and a half.
Nancy R. Peck