CALAMITES AND LYCOPODS 



38s 



Sterile. The lower sporangia are larger than the upper 

 ones, and bear four large spores {megas pores). They are 

 megasporangia, and the leaves are megasporophylls. The 



Fig. 281. — Sdaginella Marlcnsil. a, vegetative branch; h, portion of 

 the stem, bearing cones {x)\ c, longitudinal section of a cone, showing 

 microsporangia {mic. sp.) in the axils of microsporophylls, and megaspor- 

 angia in the axils of megasporophylls; d, microsporangium with micro- 

 sporophyll; e, microspores;/, portion of wall of sporangium, greatly magni- 

 fied; g, megaspore; h, microsporangium opened, and most of the micro- 

 spores scattered; i, megasporangium, with megasporophyll; h, same, 

 opened, showing the four megaspores. 



smaller sporangia {microsporangia) are subtended by 

 viicrosporophylls, and bear numerous small spores {micro- 

 spores). In some species the two kinds of sporophylls 



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