GROUPS OF PLANTS. 



53 



(3) In the Anthoceros Group (Fig. 31) the gametophyte 

 is thallus-like and very simple in structure, the sexual organs being 

 embedded in the thallus. The sporogonium is characterized by a 

 bulbous foot and an elongated, 2-valved capsule. Like the thallus 

 it develops chlorophyll and possesses stomata resembling those 

 found in certain groups of mosses and higher plants. 



Fig. 31. Anthoceros gracilis, one of the liverworts. A, thallus with 4 sporogonia; 

 B, a ripe elongated sporogonium, dehiscing longitudinally and showing two valves between 

 which is the slender columella; C, D, E, F, various forms of elaters; G, spores. — After 

 Schiffner. 



MUSCL 



In the Mosses the archegonia always form the end of the 

 axis of a shoot, whether this be a main one or a lateral one. As 

 has already been stated (p. 48) the sexual organs are sur- 

 rounded by leaves or leaf-like structures, known as perichsetia or 

 perichsetal leaves, and by hair-like structures or paraphyses, both 

 of which are considered to act as protective organs. Sometimes 

 the groups of sexual organs together with the protective organs 



