Biology of Fegatella conic a. 105 
classification is adopted by Schiffner (1893) in Engler and Prantl’s 
‘ Pflanzenfamilien.’ The female receptacle of the Compositae was shown 
by Leitgeb to consist of a branch-system, having a number of growing- 
points, from each of which archegonia are formed in acropetal succession ; 
to this group Leitgeb referred Marchantia , Preissia , Lunularia , Dumortiera , 
and, doubtfully, Fegatella . In the Astroporae and Operculatae, however, 
the female receptacle was believed by Leitgeb to be merely a dorsal 
outgrowth of the thallus, formed behind the growing-point, which might in 
some cases ( Clevea , Plagiockasma) continue to grow and to produce several 
receptacles in succession. Recent observations have shown, however, that 
the distinction drawn by Leitgeb between the receptacle of his * Compositae * 
and ‘ Operculatae ’ cannot be maintained. Thus Cryptomitrium and Fim- 
briaria have generally been regarded as belonging to the lower type, but 
Abrams (1899) has shown that in the former genus the receptacle is formed 
directly from the apex of the shoot, which divides to form five or six 
growing-points, each producing about five archegonia in acropetal succession ; 
and Campbell (1895, p. 57) found that Fimbriaria calif ornica also shows 
a typical composite receptacle, the apex branching to form four growing- 
points, each of which gives rise to two or three archegonia. Moreover, 
Solms-Laubach (1897) has shown that although the genus Exormotheca is 
referred by Schiffner (1893, P* 29) to the Astroporae of Leitgeb, its bilobed 
receptacle presents two groups of archegonia, each group containing as 
many as five, though the number may be reduced to one ; hence this form 
also would belong to the Compositae rather than to the lowest group of 
the Marchantioideae. 
From the considerations here brought forward, it would appear that 
Fegatella represents the simplest type of the Compositae, the female 
receptacle being a branch-system, in which each growing-point usually 
gives rise to a single archegonium. In this respect Fegatella forms an 
interesting member of the series of forms that bridge over the gap between 
the two extremes — the simple dorsal outgrowth of Clevea and Plagiockasma 
and the elaborate branch-system of Marchantia polymorpha . 
Archegonium (Fig. 31). 
Since the number of archegonia developed in each receptacle is so 
small, and their differentiation is practically simultaneous, Fegatella is not 
a very suitable form in which to study in detail the cell-divisions that 
occur in the young archegonium. However, sufficient stages were observed 
to show that in this respect Fegatella agrees closely with the descriptions 
given for M archantia by Strasburger (1870) and by Kny (1890), for Preissia 
by Janczewski ([872, p. 386), and for Targionia and Fimbriaria by Campbell 
( i 895, p. 52). Each archegonium arises from a superficial cell which 
projects above the surface and becomes divided by a transverse wall ; the 
