EXERCISE 97 

 REPRODUCTION OF MOSSES 



Materials. Collections of moss bearing the long-stalked spore 

 cases, and material with archegonia and antheridia; prepared sec- 

 tions of archegonia, antheridia, and sporophytes. 



Directions for work. Most of the facts of the reproduction of 

 mosses can be worked out only by the aid of the compound 

 microscope. With the exception of 1 this exercise had better 

 be omitted unless the class is an advanced one. 



1. Some of the moss plants will bear at the top a leafless 

 stem from one to three inches tall, with an enlargement at the 

 top. When disturbed, clouds of spores may be given off from 

 the enlargement, or sporangium. These are sexual spores. 



2. Antheridia and archegonia. These may be dissected out 

 from the tips of the leafy stems with needles and examined 

 by the aid of the microscope. A more careful study can be 

 made from stained sections. (See textbook for details.) 



3. The sporangium and stalk (sporophyte) grows from a 

 fertilized egg. (See textbook.) Development of the sporophyte 

 may be followed in sections. 



References 



BERGEN and CALDWELL. Practical Botany, pp. 260-265. 

 BERGEN and CALDWELL. Introduction to Botany, pp. 264-266. 



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