544 



LIFE-HISTORIES 



relatively much greater stem-development, and in having the leaf- 

 members n'horlcd, the sac-lcavcs in cones, and the spores with elaters. 



194. The club-mosses (Class Lycopodinae) are well tj-pi- 

 fied by Lycopodium (Fig. 166) which is popularly regarded 

 as a kind of "moss" because of the general resemblance of 

 the leaves and stems, in form and proportionate develop- 

 ment, to the pseudo-leaves and pseudo-stems of many true 

 mosses. 



Fig. 372. — Club-moss [Lycopodium sp., see Fig. 166.) A, gametophyte (^), 

 showing archegonia (ar) and antheridia (an). B, old gametophyte (p) 

 nursing a young sporophyte, Y- C', anthcridium ("ja) almost ready 

 to discharge its spermatazoids. D, archcgonium, cut vertically to show 

 the egg-cells (o), the upper canal-cells dissolved into mucilage (he), 

 and tlae lower canal-cell (6c), -J". (Treub.) 



The gametophyte (Fig. 372) is bisexual and massive, as in the 

 adder-tongues, and mostly saprophytic; and the cmbr3'o resembles 

 that of a fern in having but a single cotyledon. Its development is 

 essentially like that of the next type to be described. 



The stem often forks but sliows no secondary thickening. 

 The leaves are unbranehed, and in some species are all much 

 alike, while in other cases the sac-leaves are smaller than the 

 foliage leaves, are crowded into cones, and serve chiefly as 

 protective scales for the sporangia. Each sac-leaf bears but 

 a single spore-case on its upper surface near the base. There 

 are no elaters. 



