THE LYCOPODIACE^. 



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not extend to the apex. They are arranged on the stem 

 and branches in from four to sixteen rows, the number 

 depending upon the species. These numerous short 

 leaves, mostly standing out from the. stem, make many 

 species look exceedingly like mosses, especially when 

 not in fruit ; but even then they may be distinguished 

 from mosses by the fact that their stems contain pro- 

 nounced fibre-vascular bundles, while those 

 of the mosses do not. 



The lycopodiums are among the latest of 

 the fern allies to fruit. Some in the northern 

 States do not shed their spores 

 until late in October. The spore- 

 cases are always borne at or near 

 the tips of the branches. In one 

 type they are in the axils of 

 unchanged leaves ; in another the 

 leaves are more or less reduced 

 and yellow in colour, forming 

 cone-like spikes which in some 

 species are borne above the 

 foliage leaves on slender stems. The sporangia or spore- 

 cases, one in the axil of each leaf, are one-celled kidney- 

 shaped structures with thin tough walls. The spores are 

 very abundant, and bright yellow in colour. Undevel- 

 oped spore-cases are often found above and below the 

 zone of fruitful sporangia. 



The prothallium of Lycopodiinn is still imperfectly 

 known. In the species in which it has been studied it 

 usually consists of a cylindrical mass of pale cells either 

 wholly or partly underground and bearing both male and 

 female elements. These pale prothallia, lacking the 

 green colouring-matter of ordinary plants, cannot secure 



Sporophyll and 

 Spore-case. 



A Fruiting- 

 spike. 



