14 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



until they are mature. The sporophyte is much simpler than 

 in any of the other Bryophytes and consists of a spherical 

 capsule only, which absorbs through its entire surface. The 

 capsule contains nothing but spores, and these are at first 

 enclosed by the capsule wall, consisting of a single layer of 

 cells. As development advances, this wall gradually disap- 

 pears, and the mature spores lie free within the calyptra. They 

 are set free by the decay of the surrounding tissues of the 

 gametophyte, and are dispersed largely through the agency 

 of water. 



The Marchantiacese are all terrestrial, some of them grow- 

 ing on shaded rocks or in their crevices and others on damp or 

 wet earth. The thallus is more highly differentiated than 

 in the Ricciaceae, and in the larger species sometimes reaches 

 a length of twenty centimeters or more and a width of ten 

 millimeters. The branching is normally but not invariably by 

 forking. The New England species are more or less peren- 

 nial but some of them develop sporophytes during the first 

 year. 



Except in a few genera which do not occur in the eastern 

 United States, the archegonia are borne on modified branches 

 or outgrowths of the thallus known as carpocephala. These 

 consist of two parts, an apical discoid or conical expansion 

 and a basal cylindrical stalk. Sooner or later the stalk elon- 

 gates and carries the expansion, to which it is attached in a 

 peltate manner, high up above the surface of the thallus. As 

 the sporophytes mature, they extend horizontally from the 

 margin of the expanded portion or else hang downward from 

 its lower surface. They are more complex than in the Ric- 

 ciaceae and not only develop a capsule with a persistent wall but 

 also a foot and a short stalk, although the line of demarcation 

 between the two latter organs is not always clearly defined. 

 The spore cavity contains not only the spores but also a large 

 number of peculiar bodies known as elaters, each of which 

 consists of a long and slender cell with a thin cell wall, 

 strengthened on the inside by one or more spiral bands of 

 thickening. When the spores become mature, the stalk 

 elongates slightly, the calyptra is ruptured, and the wall bursts, 

 either by means of irregular valves extending backward from 

 the apex, or else by a circular line, which leaves the basal 



