Mar chant idles. 
99 
Corsima, though showing distinct affinities with the Ricciace<e» 
makes some important advances upon that family, especially in the 
more definite organisation of the receptacles, or gametophores, and 
Fig. 8. Corsinia marchantioides. Longitudinal sections of thallus. A, shows 
the outgrowth arising in the midst of the archegonial group ; B, a later stage, 
with a young sporogonium. After Leitgeb. 
in the structure of the sporophyte, as well as in that of the thallus. 
The curious outgrowth which arises in the midst of the archegonia 
(Fig. 8) foreshadows the elaborate archegoniophore, or carpo- 
cephalum, of the higher Marchantiales. 
Boschia, with a single species, is found only in Brazil; our 
knowledge of this interesting plant is due to Leitgeb. 1 It has the 
habit of a xerophilous Riccia. The large two-rowed ventral scales 
roll up over the narrow thallus in the dry state; the air-chambers 
contain well-developed filaments. The antheridia are developed in 
a row on the midrib of the male plant, but are not collected into a 
definite antheridiophore. The archegonia are produced in groups 
1 Unters, iv., p. 57. 
