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A TEXT-BOOK OF BOTANY 



speaks of a moss and a fern, the gametophyte is referred 

 to in the former case and the sporophyte in the latter. 

 This means that, in passing from mosses to ferns, plants 

 have transferred the chief work of food manufacture from 

 the gametophyte to the sporophyte, which has thus become 

 the conspicuous generation. The leaves of mosses, there- 

 fore, are gametophyte leaves; while the leaves of ferns are 

 the first sporophyte leaves. A common and brief statement 

 of the contrast between the two groups is that mosses have 

 a leafless and ferns a leafy sporophyte. How the leafless 

 sporophyte has become a leafy one is an interesting but un- 



FIG. 182. Sporangia, of ferns: A, elongated sori, with pocket-like indusia; , round 

 eon, with shield-like indusia. 



