Lincolnshive Liverworts. 87 
and one thallus overlaps another, so that large green patches are 
usually formed by such species. The epidermal cells contain 
stomata, more or less like those in the leaves of the higher plants. 
In the foliaceous forms, e.g., Lophocolea, there is a well-marked 
stem, which, however, has no proper vascular-tissue, but is compos- 
ed of simple elongated cells throughout. he true leaves are usually 
in two rows; they are simpie in structure, having one cell only in 
thickness. There are often small scale leaves, as in the frondose 
forms, on the lower side of the stem, where rootlets are also 
found. 
As the Liverworts depend on surface water—the rootlets only 
penetrating the ground for a short distance—there are many 
interesting developments for water-holding, ranging from a 
hollow leaf, or a lacineate leaf (which acts like a sponge), to a 
complicated pitcher, comparable with the vessels borne by 
Utricularia. 
Dealing now briefly with reproduction in Liverworts, we find 
an interesting vegetative method, or budding. The buds, or 
_ gemme, may be simply borne at the ends of shoots, as in Kantia, 
or are formed in a “cup,” as in Marchantia, where the cup is 
circular, or as in Lunularia, where the cup forms only half a 
circle, or is semilunar in shape. 
_ In the sexual mode of reproduction there is much variety, so far 
as the unessential elements—the spore bearer, etc., are concerned 
«But in the form of the essential elements there is, as would be 
i expected, considerable unformity. If we take a simple case, such 
as Pellia, we find that in the autumn a number of Archegonia, 
not visible to the naked eye, are developed at the apex of any 
female thallus, while antheridia are at the same time found em- 
bedded i in the male thallus, appearing to the naked eye as small 
round spots. When the antheridia are ripe and the plant is wet 
enough, antherozoids emerge and swim about until they reach 
the archegonia, down the neck of which they make their way and 
fe tilize the oosphere. Asa result the sporogonium is developed, 
which consists, when mature, of a pellucid stalk bearing a dark- 
looking sphere at the top—a case filled with spores. The spore 
Case bursts and the spores are disseminated and form new plants, 
