Bryophytes Are Seedless Plants Without 
DISCUSSION
Bryophytes are seedless plants without specialized water conducting tissues. Bryophytes include mosses (phylumBryophyta), liverworts (phylum Marchantiophyta Hepatophyta), and hornworts (phylum Anthocerophyta). They are plants that virtually everyone has seen, but many have ignored. The most commonly encountered group is the green mosses that cover rotting logs, anchor to the bark of trees, and grow in the spray of waterfalls, along streams and in bogs. Even though mosses often thrive in wet habitats, many mosses and some liverworts can survive in relatively dry environments such as sandy soils and exposed rock outcrops.
The liverworts can take leafy forms, which are very similar superficially to mosses, but differ in the details of leaf size and arrangement. Other liverwort genera are characterized by a thallus made up of relatively small, flattened, ribbon like segments of photosynthetic tissue, which have the general appearance of short, branched pieces of rich dark green egg noodles or linguini.
The leafy liverworts and the mosses differ in the appearance of their spore forming structures. The mosses have thin stalks called seta extending from the ends of leafy branches. Seta bears capsules, which produce spores. The leafy and thalloid liverworts have very small, balloon shaped spore producing stages that remain virtually hidden within, and totally dependent upon, the photosynthetic plant tissues. The third major group of bryophytes is the hornworts. They received this common name because their spore producing structures, called sporangia, are generally long, slender, hornlike, and without capsules. More than eighteen thousand different bryophyte species have been identified throughout the world, and there are perhaps ten thousand species of moss, approximately eight thousand liverwort species, and only a little more than one hundred species of hornworts.
Marchantia thallus a complex thallose liverwort the thallus is many cells thick and the cells in
Bryophytes are seedless plants without specialized water conducting tissues. Bryophytes include mosses (phylumBryophyta), liverworts (phylum Marchantiophyta Hepatophyta), and hornworts (phylum Anthocerophyta). They are plants that virtually everyone has seen, but many have ignored. The most commonly encountered group is the green mosses that cover rotting logs, anchor to the bark of trees, and grow in the spray of waterfalls, along streams and in bogs. Even though mosses often thrive in wet habitats, many mosses and some liverworts can survive in relatively dry environments such as sandy soils and exposed rock outcrops.
The liverworts can take leafy forms, which are very similar superficially to mosses, but differ in the details of leaf size and arrangement. Other liverwort genera are characterized by a thallus made up of relatively small, flattened, ribbon like segments of photosynthetic tissue, which have the general appearance of short, branched pieces of rich dark green egg noodles or linguini.
The leafy liverworts and the mosses differ in the appearance of their spore forming structures. The mosses have thin stalks called seta extending from the ends of leafy branches. Seta bears capsules, which produce spores. The leafy and thalloid liverworts have very small, balloon shaped spore producing stages that remain virtually hidden within, and totally dependent upon, the photosynthetic plant tissues. The third major group of bryophytes is the hornworts. They received this common name because their spore producing structures, called sporangia, are generally long, slender, hornlike, and without capsules. More than eighteen thousand different bryophyte species have been identified throughout the world, and there are perhaps ten thousand species of moss, approximately eight thousand liverwort species, and only a little more than one hundred species of hornworts.
Marchantia thallus a complex thallose liverwort the thallus is many cells thick and the cells in
References: Conard, Henry Shoemaker, et al. How to Know the Mosses and Liverworts, 2nd ed. New York: McGraw-Hill, 1980. Malcolm, Bill, and Nancy Malcolm. Mosses and Bryophytes: An Illustrated Glossary. Portland, OR: Timber Press/Micro-Optics Press, 2000. Shaw, A. Jonathan, and Bernard Goffinet, eds. Bryophyte Biology. New York: Cambridge University Press, 2000.