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THE AMEBIC AN NATURALIST [Vol. XLVI 



like Porella or Frullania, }s a very gradual one. It is very clear 

 that this tendency towards leaf-development has arisen in a 

 number of quite disconnected genera, and this of course suggests 

 a multiple origin for the Acrogynae. 



Cavers proposes four families of the lower, or anacrogynous, 

 Jungermanniales, viz., Aneuraceae, Blyttiaceae, Codoniaceae, Calo- 

 bryaceae. lie thinks that the first three are more or less arti- 

 ficial, and it is very certain that it will be necessary when some 

 of the less known genera are more fully investigated, to make a 

 radical revision of these families. The Calobryaceae, on the other 

 hand, forms a sharply defined and natural family, comprising 

 two genera, Eaplomitrium and Calobryum. Cavers concludes 

 that there are two main lines of development within the Anacro- 

 gyme. one including the Codoniaceae and Calobryaceae, the other 

 tlic Hlyttiaccw and Aneuraeea>. suggesting that the two latter 

 families might perhaps be better united into a single one. There 

 seems to be little question that the two families are closely related 

 through such forms as J'mbraculum and Podomitrium. 



There is much uncertainty as to the limits of certain genera. 

 This is especially the case with the genus Calycularia, to which 

 have been assigned species which further investigation has shown 

 to belong to quite different families. The writer has had occa- 

 sion recently to examine carefully the structure of Calycularia 

 radiculosa, a rare species from Java. Schiffner concluded that 

 this species should be removed from the genus Calycularia, of 

 the family Codoniacea\ and united with Morkia, a member of 

 the Blyttiaceae. While it is certainly distinct from the true 

 species of Calycularia, it is equally certain that it can not be 

 assigned to Mbrkia. It will probably have to be separated into 

 a distinct genus with characters intermediate between those of 

 the Codoniaceae and the Blyttiaceae. In short, it is very clear 

 that at present a satisfactory classification of the group is not 

 feasible. 



The Aneuraceae and Blyttiaceae show an interesting type of 

 serialization of the thallus which is wanting in the Codoniaceae 

 and Calobryaceae, where the tendency is toward the development 

 of leaf-like lobes foreshadowing the leaves of the leafy liver- 

 worts. In Podomitrium and Umbraculum, assigned respectively 

 to the Blyttiaceae and Aneuraceae, the thallus is differentiated 

 into a prostrate cylindrical rhizome and erect dichotomously 

 branched fan-shaped shoots, which resemble very closely the deli- 



