Lynn Johansen, age 14, of Nogales, Ariz., for her question:
WHERE CAN THE LIVERWORT BE FOUND?
Liverworts are small green plants that are closely related to the mosses. They are found in all parts of the world. They grow in damp, shady places and can be found on rocks and barks and sometimes even in water.
The lower liverworts are shaped like minute leaves of seed plants with many lobes. The main body of the plant, which looks like a leaf, is called the thallus.
Liverworts get their name because the thallus is often shaped like the human liver. Superstitious persons once thought that liverworts could cure liver diseases.
Tiny rootlets grow from the underside of the thallus. These structures are called rhizoids. The absorb water and the minerals that the liverwort needs for nourishment. The rootless also hold the plant to the rocks and trees on which it grow.
New liverwort plants are produced in several different ways. One way involves two different generations or stages, and is called alternation of generations.
The thallus is the sexual generation. It is called the gametophyte. Male and female sexual structures grow on the thallus. The male structures produce sex cells called antherozoids. The cells produced by the female structures are the eggs.
Later the antherozoids swim through the moisture on the plant until they reach the eggs in the female structure. An egg is fertilized when the two cells join each other.
The fertilized egg grows into a tiny new structure, the sporophyte. The sporophyte is the nonsexual generation of the plant. It lives on the liverwort thalius and soon produces spores. Spores are tiny one celled structures that grow into new organisms.
The liverworts are among the lowest plants that have this two stage type of reproduction.
Scientific classification for liverworts is Hepaticate. They are in the Bryophyte division.
Bryophyte is the name of one phylum or division of plants in the sub kingdom Embryophyta, or plants forming embryos. The bryophytes are the mosses and the liverworts.
Some of the plants in this group have leaves but others do not. None of the bryophytes have true roots.
In most cases the bryophytes reproduce by means of single cells called spores or by means of sex cells. The spores grow into a leaflike, or fibrous, young plant called the thallus. The thailus produces male and female cells which unite to form a small, new plant attached to the old plant. The new plant, called the eporophyte, produces spores which grow into the common thailus again.
Certain plants called moss are not true mosses. The Spanish moss which hangs from the branches of trees in the South is a flowering plant that belongs to the pineapple family.