SPORES AND THALLIDIA. 



15 



The last division of plants wherein the spores are formed deep down in a tissue 

 is that of the Muscinese, which include Mosses and Liverworts. In these plants the 

 spore-producing generation consists of a cellular body, which has arisen from the 

 fruit, is usually seated on a stalk, and in shape is cylindrical, pyriform, or more or 

 less spherical (c/. figs. 191 3,4,7,8,15-) ^g must here remark, by the way, that botanists 

 used formerly to look upon this sporogenous generation of the Moss erroneously 



Fig 191.— Mosses. 



i Polytrichum commune, the sporogonium to the left concealed by the cap, the sporogonium to the right exposed, s The same 

 Moss in an earlier stage of development. 8 Sporogonium of Polytrichum commune with its lid. ■• The same after the lid 

 has fallen off. * Bryum ccespiticium. « Sporogonium of the same Moss with its cap. ' The same without the cap, but 

 with the lid still on. s The same after removal of the lid, showing the teeth (peristome). » A piece of the peristome. 

 10 Antheridia, Archegonia, and Paraphyses of Bryum ccespiticiicm. n Hylocomium splendent. '2 Sporogonium of 

 Hylocommm splendens. is Andrcea rupestris with burst sporogonium. " Sphagnum cymbifolium, its spherical sporogonia 

 still covered by their lids in the left-hand specimen, is A single sporogonium of the same Moss, i, «, «, ", " natural 

 size ; s, 4, 6^ 7, 8^ 12, 13, 15 X 5; 9, 10 X 150. 



as the fruit itself. The only structure rightly to be considered as the Moss-fruit is 

 that in which the embryo is produced as a result of fertilization. If afterwards a 

 new generation springs up from the embryo which has been formed in the interior 

 of the fruit, this generation cannot any longer be described as a fruit even in cases 



