ASPIDIUM SPOROPHYTE 301 



round the punctum vegetationis : after this treatment 

 it will be easy to observe with a pocket lens 



1. The apical cone (punctum vegetationis), a 

 rounded papilla, occupying a central and terminal 

 position in the flattened apical region. 



2. The young leaves, situated round the apical 

 cone, and successively larger the further they are from 

 the apex. Note the circinate curvature which appears 

 at an early period in their development. 



XI. With a sharp razor, wet with water or with very 

 weak spirit if the material be fresh, or with strong 



FIG. 13. View of a model of a three-sided pyramidal (or tetrahedral) apical cell, as 

 seen from above: the walls de, f g, hk, denote successive walls by which 

 segments have been cut off from the growing apical cell : i is the apex of the 

 pyramidal cell, at which point the three youngest segmental walls cut one 

 another. (After Sachs.) 



spirit if it has been previously hardened in alcohol, 

 remove the extreme apex of the punctum vegetationis, 

 taking care to cut accurately in a transverse plane : 

 mount in water, or in weak glycerine, and examine 

 with a low power. If the section be thin enough, it 

 will be seen that a large cell of triangular outline 

 occupies the centre of the apical cone, while the cells 



