REPRODUCTION IN CRYPTOGAMS. 



441 



of flowerless plants. Comparative investigations have, however, 

 shown that such gradations do exist, and that the chain of exist- 



fertilization is shown in the figure. Of the more complicated cases this is not 

 the place to speak ; their treatment, as well as that of all the simpler forms, 

 may be looked for in Volume III. 



Specimens for this demonstration of the different stages of reproduction are 

 to be procured at different seasons. As will be seen from the figure, most of 

 the features are so nearly superficial as to need no particular sections for their 

 exhibition. 



(5) True mosses and their allies are characterized by the possession of an 

 archegonium or flask-shaped body containing a central cell in which is the 

 oosphere. The ob'sphere is fertilized by immediate contact with antherozoids 

 which are formed in antheridia ; as a result of the fertilization, there is 

 produced a spore-case filled with spores. 



In the examination of the fructification of a moss, the plant must be taken 

 at an early stage, and search must be made for the sexual organs by removal of 

 the flower-like cluster of leaves 

 at the summit of the minute 

 stalk. If the removal is success- 

 fully performed, and the plant is 

 in the right condition, a group 

 of threads like those shown in 

 the. figure will be plainly seen. 

 Among these are to be found 

 some flask-like bodies, the arche- 

 gonia, and either on the same 

 receptacle or on another plant 

 of the same species the male 

 organs, one of which, greatly 

 magnified, is shown in Fig. 212. 

 Under a very high power the 

 escaping antherozoids can be 

 seen. When fertilization has 

 taken place, the archegonium 

 goes on in its development, be- 

 coming, after many intermediate 

 steps, the capsule or "fruit" of 

 the moss, covered by a sort of 

 hood or cap, and tightly closed 

 at its month by a lid. Removal 

 of the lid discloses the teeth of 

 the mouth (peristome) and the 

 spores within. Upon germina- 

 tion, a spore gives rise to slender 

 filaments among which is pro- 

 duced the minute moss-plant with the sexual organs figured in the sketch. 



PIG. 212. Punaria hygrometrica, a moss. 1. Longitudinal section through the 

 upper part of the plant with archegonia, a, and leaves, b. 2. Antheridium bursting 

 and allowing escape of the antherozoids, a. (Thome.) 



