Liverwort

Liverworts are a class of terrestrial, non-vascular plants that can be found globally and consist of nearly 7000 species. They most commonly grow in moist, shaded areas such as damp rocks, soil, or tree trunks . Liverworts can be categorized into 2 groups: thallose liverworts or leafy liverworts depending on their growth form. Liverworts serve as a source of food for animals and aid in the decay of logs and rocks.

Kingdom	Division	Class
Plantae	Marchantiophyta	Hepaticae

Thallose Liverworts

Thallose liverworts grow in a flat structure, with rubbery leaves and can be found on soils with high moisture or damp rocks . The structure is formed by thallus which is a mass of uniform flattened cells, except for the capsules which contain sporophytes. Early species had thick and opaque structures but currently, the appearance of thallose liverworts can vary from thick and opaque to thin and clear depending on the genus. In some species, the thallus can also form branches that grow in a 'Y' formation.

Leafy Liverworts

Leafy liverworts bear a similar resemblance to mosses and ferns as they have small leaves that overlap each other and grow in pairs on their stems. The leaves are quite small and are only ~1 mm in size with a single cell layer. The upper 2 layers of leaves are designed to be larger than the descending rows and in some species there may be a lower layer that consists of lobed leaves that are referred to as underleaves.

Life Cycle

Since liverworts do not have a vascular system, they reproduce through the sporophyte. Haploid cells are released from the sporangium all at once and are distributed by wind or water, where they germinate into thalli gametophytes. The sporangia doesn't survive for much longer after dispersal. The gametophytes fall onto different plants, attaching themselves to individual plants, where male and female gametangia develop. Once developed, male gametes will fertilize the female gametangium to create a zygote. This zygote will stay attached to the parent while forming into a sporophyte and create it's own spore-producing cells. Once these cells undergo meiosis, they will form spores, and thus restart the cycle.