XIII 



LYCOPODINEAi 



523 



phylls differ but little in appearance from the ordinary leaves, 

 but in the heterophyllous ones they are smaller tlian the other 

 leaves, and form a strobilus much like that of Lycopodium, but 

 usually less conspicuous. 



The strobilus (Hieronymus (i), p. 653) may be either 

 erect or horizontal; much more rarely it is pendent, and there 

 appears to be a certain relation between the arrang-ement of the 

 sporophylls and the position of the strobilus. Where it is up- 

 right the sporophylls are all alike, and dis])osed radially about 

 the axis. Where the strobilus is horizontal it is more or less 

 markedly dorsiventral in structure. In 5^. selaginoides and 5". 

 deflexa there is a more or less perfect spiral arrangement of the 



Fig. 302. — A, Part of a fruiting plant of Selaginella Kraussiana, X3; sp, sporangial 

 strobilus; R, young rhizophore; B, longitudinal section of the strobilus, X5; >"a, 

 macrosporangium ; mi, microsporangium. 



Sporophylls, but in all the other species they are four-ranked. 

 Usually in the latter case the sporophylls are alike, but there 

 may be the same difference in the dorsal and ventral leaves of 

 the dorsi-ventral strobili that is found in the sterile shoots of the 

 same species. 



The basal leaves of the strobilus may be sterile, but usually 

 each sporophyll subtends a sporangium. In ^. Kraussiana, 

 and many other species of the same section of the genus, there 

 is but a single macrosporangium developed — the first formed 



