REPRODUCTIVE ORGANS OF HEPATICACE., B17 
(fig. 853, b). At the base of the perigone, a number of cellular 
filaments, pericheetial leaves, or paraphyses, are also occasionally 
to be found (fig. 833, ¢, c). 
As in the case of Mosses, the fertilised germ-cell does not 
directly develop a new plant like its parent, but after fertilisa- 
tion the germ-cell enlarges and bursts through the epigone, and 
forms a sporangium or capsule; the epigone either remaining as 
a sort of sheath round the base of the sporangium, which is 
called the vaginule, or its upper part is carried upwards as a sort 
of hood or styloid calyptra. 
The sporangia vary much in different genera. In Marchan- 
tua they are formed of two layers of cells: one external, called 
the cortical or peripheral layer; and one internal, in which the 
spores, &c., are developed. The cells of the cortical layer 
exhibit spiral fibres, like the cells constituting the inner lining 
of the anthers in Flowering Plants. The cells forming the 
internal layer are thus described by Henfrey :—‘ At an early 
period the cells of the internal mass present the appearance of a 
large number of filaments radiating from the centre of the spo- 
rangium to the wall. ‘These soon become free from each other, 
and it may then be perceived that some are of very slender 
diameter, and others three or four times as thick. The slender 
ones are developed at once into the long elaters (fig. 834, ¢) 
characteristic of this genus, containing a double spiral fibre, the 
two fibres, however, coalescing into one at the ends. The thicker 
filaments become subdivided by cross partitions, aud break up 
into squarish free cells, which are the parent cells of the spores, 
four of which are produced in each.’ The sporangia in this 
genus are situated on the under side of the receptacle (jig. 
832, r), and vary in form; they burst by valves. 
In Jungermannia the sporangia are elevated upon stalks 
arising out of a vaginule; they are more or less oval in form, 
and open by four valves which spread in a cross-like form ; they 
contain spore-cells and elaters with a single spiral filament (jig. 8). 
in Anthoceros the sporangia open by two valves, and have a 
central axis or columella ; they are of an elongated, tubular, or 
conical form, and are situated on a short stalk, and contain 
spore-cells and elaters, but the latter have no spiral fibres in 
their interior, and are much simpler in their structure than those 
just described as found in Marchantia. In Riccia the sporangia 
are imbedded in the substance of the frond, and have neither 
elaters nor columella. They have no regular dehiscence. 
The spores have usually two coats, like pollen-cells ; and the 
outer coat also frequently presents markings of different kinds; 
but in Marchantia the spores have but one coat. They mostly 
germinate without any well-marked intermediate prothallium, 
although some produce a kind of prothallium in the form of a 
confervoid mass or protonema, like a Moss (see page 375), 
