340 TLA NT STUDIES 



sporangia, wliieli lu'oduce si^ores of but one kind, hence 

 tliese plants are honiosporous ; and as the sporangia origi- 

 nate in eusporangiato fasliion, Eqti iaet um has the liomospo- 

 rous-eusporangiate combination shown Ijy one of the Fern 

 groups. It is interesting to know, liowever, that some of 

 the ancient, more liighlj organizeil members of this group 

 were lieterosporous, and tliat tlie 2)resent forms liave dice- 

 cious gametoi)liytes. 



Lycopodiales ( Clith-mDSfics) 



331. General characters. — Tliis group is now represented 

 by about live hundred species, most of which belong to 

 the two genera Lijcdpudinin and hidayiiii'Ua, the latter 

 being much the larger genus. The plants have slender, 

 branching, prostrate, or erect stems completely clothed 

 with small foliage leaves, having a general moss-like ap- 

 pearance (Kigs. oO(i, 307). Often the erect branches are 

 terminated l)y conspicuous conical or cylindrical strobili, 

 which are the "clubs" that enter into the name " C'luV 

 mosses." There is also a certain kind of resendjlance to 

 miniature pines, so that the name " Ground-pines '' is some- 

 times used. 



Lycopodiales were once much more ahundant than now, 

 and more higldy organized, forming a conspicuous part of 

 the fcn'cst vegetation of the Coal-mea.sures. 



Om> of the distinguishing marks of the group is that the 

 sperm does not resemble that of the other Pteridophytes, 

 but is of the IJryophyte typo (Fig. 377) ; that is, it con- 

 sists of a small body with two cilia, instead of a large 

 spirally coiled body with many cilia. Another distinguish- 

 ing cliaracter is that there is but a single sporangium pro- 

 duced by each sporophyll (Fig. 30G). This is in marked 

 contrast witli the Filicales, whose leaves bear very numer- 

 ous sporangia, and with the Equisetales, whose sporojihylls 

 bear several sporangia. 



