Liverwort

Like mosses and higher plants, liverworts use chlorophyll-a, chlorophyll-b, and carotenoids as photosynthetic pigments and store their food reserves as starch. As in mosses and higher plants, their cell walls are composed of cellulose.

Like mosses and hornworts, liverworts are restricted to moist environments for two principal reasons. First, they lack a vascular system for efficient transport of water and food. Second, their sperm cells must swim through water to reach the egg cells.

The thalli of most liverworts have dorsiventral morphology. In other words, they have distinct front and back sides. In this respect, liverwort thalli are similar to the leaves of higher plants.

The name "liverwort" is centuries old and was given to these plants because their thalli are liver-shaped. In earlier times, people believed in the doctrine of signatures. This dictated that a plant part which resembles a bodily organ can be used to treat diseases of that organ. Thus, liverworts were used to treat diseases of the liver. Western science has long since discredited the "doctrine of signatures," although it is still advocated by various "New Age" and other pseudoscientific movements.