260 



LYCOPODIACE^E. 



ground it is separated genericaly from Lycopodium, in 

 which the spores are all alike. 



Common Club-moss, or StagVhorn Moss (Lycopodium 

 clavatum} is very common on mountain-sides and upper 



FIG. 203. Lesser Club-moss, a, scale with sporange containing large 

 spores (macrospores) ; b, single macrospore ; c, scale with sporange con- 

 taining small spores (tnicrospores) ; d, single microspore (magnified). 



moorlands, as is also the Fir Club moss (L. Selagd). 

 The mode of reproduction of our species of Lycopodium 

 upon which but one kind of spore, and those very 

 numerous, has been found, has not yet been traced through 

 all its stages. The spore develops a subterranean pro- 

 thallium bearing both antheridia and archegonia. The 

 antheridia are ellipsoidal sacs immersed wholly in the 

 tissue of the upper stratum of the fleshy prothallium. The 

 archegonia have not been observed prior to fertilisation. 

 In Selaginella the lower sporanges of the fertile spikes 

 contain, when fully developed, usually four relatively large 

 spinulose spores (inacrospores] which even before they 

 are shed bear upon the inner face a narrow prothalloid 

 zone which becomes exposed on germination by the tri- 

 radiate rupture of the outer coat of the spore imme- 

 diately over it. In this rudimentary prothallus, which is 

 crescentic in section, bounding the cellular tissue filling 



