Just in case anyone thinks this has turned into ‘Darren’s Insanity and Humour’ blog, here is a geeky plant post:
Lithops (‘Living Stones’).
I’m sure you have all seen these and maybe even grown them, though many people struggle to flower them (the flowers are either white or yellow – see below).
What I wanted to highlight in this post is their seed distribution mechanism which involves a startling amount of movement for a plant that seemingly never changes.
After pollination (they are not self-fertile so need another Lithops plant to supply pollen) the woody and tough protective seed capsule takes up to a year to ripen and is ready to shed seed at around the same time the plant produces the following years flowers. This is in late summer or autumn when the very arid habitat is most likely to receive rain to give the young seedlings a chance of surviving.
So – how does the plant ‘know’ to release the seeds at the optimum time? It uses the rain as a trigger.
The first raindrop landing on a capsule causes the top of the capsule to fold back and open rather like the eggs in Alien! Subsequent raindrops then wash the seeds from the capsule and water them into the surrounding soil.
This is clever enough in itself but some members of this family also have inner structures in the capsule that prevent all the seeds from being washed out at once – giving the plant another chance if the first lot to be released do not survive – often because the rains were too brief. Even then the story does not end – some species even have further seeds partially embedded in the capsule walls and these only get released when the capsule rots or is abraded by the wind – sometimes years after pollination.
The capsule opening takes only seconds – the two pictures below were taken only a minute apart before and after I splashed water on the plant.