Common Liverwort an extremely variable and common plant
Nature enthusiasts and gardeners may have noticed of late the eye-catching plant structures featured in the image above. They are very common at present.
Each structure is composed of an upright, brownish stalk topped with nine green fat fingers. These fat fingers may droop down forming an umbrella shape or may stand out horizontally making a pattern like a nine-armed starfish.
The structures are very attractive especially when a group of them looks like a mini-forest of palm trees. The only problem with them is that they are tiny so examining them is a hands and knees job. A magnifying glass or hand lens is a help in revealing detail.
They are most commonly found on damp soil near a greenhouse but can also be found in a wide variety of moist habitats.
These attractive structures that are so very common at present are the heads of the mature female reproductive organs of the Common Liverwort, a plant closely related to mosses.
'Wort' is an old English name for a weed and the 'liver' part of the plant's name refers to the fact that the plant's body is often divided into fat lobes like those of a liver.
As its name states, the Common Liverwort is one of our more common species. It is also one of our larger species. It thrives in garden centres where it can become a horticultural pest and from where it gets distributed far and wide in plant containers.
Common Liverwort is an extremely variable plant with many named subspecies. One subspecies - the Mountain Liverwort - is rare and is afforded legal protection under the Flora (Protection) Order, 2015.
Common Liverworts come in separate sexes. Only females have the structures described above. Male plants have similar stalks but each is topped with a small, flattened disk with scalloped edges. Both sexes often grow side by side. When they breed, sperm is transferred by raindrop splashes.
Whether male or female, the reproductive organs arise from a mat of flat, forked, waxy green leaf-like structures. The plant has no roots; instead it anchors itself to the ground with root-like hairs growing on the backs of the leaf-like structures. These hairs function as anchors only; they cannot absorb water and minerals from the soil.
The mats of leaf-like structures are so dense that they tend to inhibit the germination of other plant seeds. They are particularly quick to colonise bare ground after a fire when liverwort spores blow in from surrounding areas.