Liverworts are not, I have to admit, the most exciting plants - except when their spore capsules explode. These simple plants have been around for over half a billion years, confined to wet places like the muddy banks of streams, where I found this thalloid liverwort called Pellia epiphylla. Liverworts' common name derives from the fact that - if you've got a vivid imagination - their flat lobes look like lobes of green liver and since, according to the mediaeval Doctrine of Signatures, any part of a plant that looked like a part of the human body was supposed to be good for curing its ills, liverworts were assumed to be good for treating liver diseases. Superstition aside, liverworts become a little more interesting at this time of year when they produce these...
.. spherical spore capsules on the surface of the thallus. These change colour, from green to black as they ripen and then suddenly (for a plant) their stems elongate, often overight, raising the capsule aloft on a glassy stalk ....
.... then four vertical splits in the capsule wall become apparent and suddenly (this time, over the course of a few minutes) .....
... the capsule splits open, revealing a mass of green spores interspersed with strange whiskery golden threads.......
.... seen here at higher magnification.
You can see a short video of these writhing threads below .....
Here they are at higher magnification, along with a spore, and below....
... at higher magnification still, when it becomes apparent that each one of those golden threads, known botanically as an elater ...
.... has a helical spring embedded in it. Inside the ripe capsule the springs were all compressed but once the capsule wall splits their force is liberated, hurling out the spores until....
.... only 'springs' and a few remaining spores are left on top of the stalk. Meanwhile most of the spores...
... like this one, magnified here about 400 times, have been scattered to the four winds, to land on some muddy stream bank and germinate to form another thalloid liverwort. It's a cycle that's been going on for half a billion years and is repeated every spring.