Brenda Simmons, age 12, of Winnipeg, Manitoba, Canada, for her question:
What are liverworts?
The soapwort plants blossom with dainty pink sprays of bouncing bet and its leaves yield a soapy lather. The toothwort plant has purple cone flowers and its leaves have toorhy notches. The liverwort is a shy little plant with greenery shaped somewhat like .the human liver.
Soapworts and toothworts add wild flowers to the wayside gardens that bloom in the spring.
The "wort" part of their names is borrowed from an Old World word meaning "pant." The little liverworts hug the ground in moist and shady places. Some types grow on the bark of trees and some grow in the water. They are such inconspicuous little plants that you might pass them by. If by chance you noticed them, you might mistake them for mosses with wide leafy foliage.
The shy little plants are well worth a closer look, perhaps with a magnifying glass. That, flat greenery suggests a layer of open fans embroidered with delicate scrollwork each fairy fan is notched with a deep cleft down the middle. Long ago, these two lobes reminded people of the shape of the human liver. This is why Old World observers named them the liverworts, meaning the liver plants. This idea, however, was carried much too far. Hopeful medicine men claimed that extracts of liverwort could cure ailments of the human liver. But this is not so.
Liverworts are distant relatives of the velvety mosses. They too are simple, flowerless plants and they too have a history dating back hundreds of millions of years. Liverworts were some of the very first plants to live upon the dry land of the earth. On a small scale, they are very successful plants. Though their way of life is very different from the larger and most complex plants that came along later.
The little liverworts do not have the usual roots, stems and branches that we expect in plants. Each fan is a "thallus," the main body of a single plant. Fine hairs called "rhyzoids" sprout from the underside of the thallus. The rhyzoids serve instead of true roots by absorbing moisture and minerals and anchoring the thallus to the ground. The green '=hallus absorbs moisture and carbon dioxide to manufacture its own sugary plant food by photosynthesis.
The simple plants grow no seed bearing flowers to hand on life to the next generation. But each small liverwort is either male or female. Cells from the two parents merge and produce a shall body: Its only duty is to produce a crop of spore seedlets. The spores grow into a new generation of parent plants. Should one of the three stages fail, some types of liverwort are able to use another system of multiplication. The upper surfaces of the male or female thallus sprouts a rash of cup shaped buds. Each of these found cupules is about 1/8th of an inch wide. When ready, it falls from the parent plant. If it is lucky, it lands on a moist and shady spot and grows into a new liverwort plant.
The three stage method of multiplication is called alternation of generations. Each parent thallus sprouts a stalked umbrella stuffed with male or female cells. Some dewy morning, when the ground is filmed with moisture, the male cells swim off to merge with nearby female cells. Rooted on the lady liverwort, the fertilized eggs become a sporebearing plant, not at all like either of its parents. The ripe spores scatter and the lucky ones grow into male and female liverworts like their grandparents.