IV.] L YCOPODIA CE^. 35 1 



bodies of two distinct kinds. One kind, the more nume- 

 rous, called a?tfhendia, contain a number of extremely 

 small vesicles, each of which liberates a spirally-twisted 

 filament, called an anfherozoid, which performs the function 

 of a pollen-grain. The other kind, called archegonia, con- 

 tains an embryonal cell which, fertilised by the antherozoids 

 set free by the antheridia, gives origin to a bud which 

 gradually developes into an independent Fern-plant. 



The antheridia and archegonia require a high magnifying 

 power for their examination. Their true nature has been 

 understood only within the last forty years. 



The stem of Ferns differs from that of both Dicotyledons 

 and Monocotyledons in its growing solely by additions to 

 the summit, below which all the tissues are completed with 

 their first formation, and in the arrangement of the fibro- 

 vascular bundles, which form an interrupted circle around 

 a cellular axis which usually decays away, so that old stems 

 become hollow. From the mode of growth of Fern-stems, 

 by additions to the extremity, they have been termed 

 Acrogens (point-growers). Some of the Himalayan species 

 of Alsophila and Cyathea (Tree Ferns) form tall woody 

 stems, well adapted to illustrate this structure. 



2. Natural Order, Lycopodiacece. — The Club-moss Family. 



Low, trailing, or tufted, usually slender, wiry herbs, with 

 small, two- (four-) rowed or scattered imbricating leaves. 

 Fructification consisting of sporanges in the axils of the 

 stem-leaves or collected in terminal bracteate spikes, con- 

 taining spores of one of two kinds, either minute and 

 indefinite, called microspores, developing antheridia, or larger 

 and definite, called macrospores^ developing a prothallus 

 bearing archegonia. 



Lycopodiaceae generally affect a humid climate, and in 



