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marked epidermis, in which are a few scattered stomata, 
and which puts out root-hairs from its under side. In the 
most highly developed.order, the Marchantiez, we find the 
first rudiments of vascular bundles, in the form of elongated 
cells containing little or no chlorophyll but often crystals. 
The leaves consist of a single layer of uniform tabular — 
cells. : 
There are two modes of reproduction: by fertilised 
oospores, and by asexual buds or gemmz. ‘The latter are. 
groups of cells which become detached from the plant, and, . 
under favourable circumstances, develope into new indivi- 
duals. In the Thalloid Hepaticez they are usually found 
at the bottom of saucer- or spoon-shaped organs, the ~ 
cupules (Fig. 349, p. 179); in other families they arise on 
the margin of the leaves or at the apex of the stem. | 
The sexual organs arise on the stem of. the mature’ 
plant ; some species being moncecious, and others dicecious. — 
The male organ, or antheridium, is a stalked, usually sphert- 
cal body, consisting of a cellular envelope or coat, and an 
internal portion formed of delicate cells. These last escape 
when the organ is mature, a spermatozoid or antherozoid 
having previously been developed in each cell, consisting of _ 
a spirally coiled thread furnished at the end with two long. 
vibratile hairs or cilia. The female organ, or archegonium 
(Fig. 422 Iv.) is a flask-shaped organ, enclosing near its base 
a large central cell. A canal leading to the central cell is- 
formed in the neck of the archegonium by the disappearance 
of the septa of the axial bundle of cells, the canal-cells ; the ~ 
canal appears to be at first closed outwardly, but opens at — 
the period of maturity by the separation of the apical cells, 
and thus gives access to the antherozoids. Before the 
antherozoids reach the central cell, the oosphere has been 
formed in the latter by free cell-formation, and gradually in- 
creases to sucha size as completely to fill up the central 
cell, the sporogontum being developed from it after impreg- — 
