XXXII 



STRUCTURE 



443 



The leaves (Fig. 116, A) arise in four longitudinal rows, 

 but, owing to the horizontal position of the plant, the two 

 rows belonging to the lower side (/ 2 ) project laterally, and 



FIG. 116. A, distal end of a shoot of Selaginella, showing the two 

 rows of small dorsal leaves (/ a ), the two laterally placed rows of ventral 

 leaves (/ 2 ), and the terminal cone (c). (Nat. size.) 



B, a microsporangium bursting to allow of the escape of the micro- 

 spores (mi. sp). 



C, a megasporangium, with four megaspores (mg. sp\ 



(A, after Sachs ; B and C, after Le Maout and Decaisne.) 



are many times larger than the two upper rows (7 1 ). Each 

 leaf bears on its upper or distal surface, near the base, a 

 small process called a ligule. 



The stem usually ends in a two- or three-sided apical 

 cell, from which segments are cut off to form the apical 



