Liverworts: Meet our Ancient Elder

The prestigious scientific journal “Nature” states that liverworts bridge marine algae to land plants; thus at present (science is always evolving) liverworts are considered to be the oldest living plants. Some have a symbiotic relationship with cyanobacteria that supply nitrogen for both plant partners as they colonized land.

Sources vary but it is estimated that there are about 8000 or 9000 species of liverworts that grow on trees, stones, the crust of the earth, or any substrate that is firm.

You can find liverworts almost anywhere on the planet but the majority prefer shade and a moist habitat.  There are a few kinds that thrive in deserts and in the Arctic.

 Some species grow as a flattened thallus (a fancy name for vegetative tissue) but most look leafy and resemble mosses. Liverworts can be distinguished from mosses by the patterns of their leaves. The former is branched and patterns are formed in two or three rows. Mosses have a radial symmetry with patterns that look like whirls or spirals. These differences are important because mosses and liverworts are closely related. Single celled rhizoids attach liverworts to substrate. (Rhizoids preceded the development of roots on land). Liverworts also have no true leaves or stems. There are other characteristics that distinguish the two but I need a lens or microscope to perceive the differences (carrying a hand lens is helpful). In general when the leaves have segments or deep lobes or no discernable stem then you are probably looking at a liverwort.

At present liverworts are classified as Marchantia.

 The most amazing aspect of liverworts from my point of view, as previously mentioned, is that they were the first plants to colonize dry land. The dates vary depending on the source but it presently appears that liverworts evolved about 500 million years ago. Equally inspiring is that liverworts survive in their original form, having endured five extinctions.

Often liverworts are small only a few inches long but sometimes the larger clumps create fantastic patterns are breathtaking to observe. On a hot summer day situate yourself by a shaded stream to observe emerald mosses while looking for those flattened bright green lobes that resemble  scalloped lime tapestries. 

 Every winter when the snow blanket seals the earth in slumber I repeat a yearly pattern of searching for the most elegant clusters of New York liverwort, one that is visible in my area at this time of year. I am perpetually in awe of the configurations that only nature could create and am struck by the fractal dimensions of these ‘trees’ that climb their elders.

This liverwort like so many others prefers a moist environment and wooded areas replete with a variety of mature trees.

 The structure of the alternate leaves is unusual. New York scalewort like others of its kind has tiny leaves. The lower lobes have the capacity to store water enabling the plant to withstand dry spells for a longer period of time. New York Scalewort has a greater tolerance for sun than most liverworts making it easier to find. 

New York scalewort forms male and female reproductive organs on different plants. After fertilization occurs spore bearing capsules (on stalks) develop in the spring. Present for a period of only two weeks the spores are then whisked away by the wind. These plants can also reproduce asexually by forming tiny buds that detach themselves from the leaves. 

Just imagine what we could learn if we considered these plants to be sentient beings, repositories of ancient knowledge. I slip into a state of awe just thinking about it.

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