PART IV. CLASSIFICATION. 



and by the relatively small neck-canal-cell. Each prothallium bears a 

 number of these organs : they are developed each from an anterior 

 marginal cell, and, as the prothallium continues to grow, the organs 

 come to lie on its upper surface. 



The female cell is an oosphere, and calls for no special remark. 



CLASS VII. LYCOPODIN.E. 



SUB-CLASS HOMOSPORE^E. 



Order 1. Lycopodiaceae. This order contains the two genera Lyco- 

 podium and Phylloglossum : the former is a large genus, six species being 



British (L. Selago, 

 inundatum, annot- 

 inum, davatum, 

 alpinum, complan- 

 atum} and com- 

 monly termed 

 Club-mosses : the 

 genus Phylloglos- 

 sum has a single 

 species (P. Drum- 

 mondii) found in 

 Australia and 

 New Zealand. 



THESPOKOPHYTE. 

 The stem. In Ly- 

 copodium the.stem 

 is slender and 

 much branched, 

 erect (e.g. L. Sela- 

 go), or growing 



FIG. 231.-Portion of Zycopodium vlavatum, somewhat smaller horizontally on 

 than nat. size : s, the cone-like flower. B a single sporophyll (b) the surface of tJ 

 from the cone, bearing a sporangium sp, which has dehisced ( x 10). ground (e.g. L. 



davatum [Fig.28i] 



annotinum), or beneath the surface as a rhizome (e.g. L. alpinum, com- 

 planatum) : the branching is in some cases dichotomous, in others mon- 

 opodial ; it may take place in all directions, or in one plane only (L, 

 complanatum). 



The leaves. In some species of Lycopodium all the leaves are alike (e.g. 

 L. Selago) ; but in most species the foliage-leaves and the sporophylls are 

 more or less widely different. 



The foliage-leaves are small and very numerous in Lycopodium ; their 

 arrangement is various, whorled, or spiral, or in decussate opposite pairs 

 (L. complanatum, etc.) : in the last case there is heterophylly (p. 41), as the de- 

 cussate leaves on the flattened sterile shoots vary in size, those on the lateral 



