More Than Mosses
Collectively, the mosses, liverworts and hornworts are called bryophytes. They are classified in the Plant Kingdom, they contain chlorophyll and they produce their own food. The bryophytes are called non-vascular plants because they lack internal conducting systems, called vascular systems, to carry nutrients through the plant. Bryophytes vary in size from a little over a millimetre tall to trailing species which grow in strands well over a metre long. Bryophytes come in many colours and these photographs show some of the variety.
The trailing moss Papillaria flavolimbata can form extensive curtains of strands.
The silvery-green moss Bryum argenteum is a widespread species which occurs from forest to town.
A moss plant consists of leaves on a stem. While there are many cells in a moss leaf, in most cases the cells are in one plane so that the leaf is only one cell thick. This is markedly different to the leaves of vascular plants which are many cells thick. Mosses produce spores in capsules that often grow on short stalks.
A hornwort in the genus Phaeoceros showing the thallose growth form and a few immature green spore capsules.
Hornworts have neither leaves nor stems. They grow as flat, green lobes called a thallose growth form. A fertile hornwort produces its spores in a long, tapering horn-like capsule that grows up from the lobes. The whole horn-like structure is the capsule and there is no stalk.
There are two types of liverworts leafy and thallose. The leafy liverworts have leaves on stems and look rather like mosses. Thallose liverworts grow as flat green lobes and some of these liverworts look like hornworts.