166 PRACTICAL BOTANY 



the pit-membrane which remains permanently in Nephrodium, 

 is often broken down on the oblique terminal walls in Pteris : 

 this is, however, exceptional for Ferns. 



e. The conjunctive parenchyma, distributed among both 

 sieve-tubes and tracheides. 



IX. From around the apical bud of a well-grown plant of the 

 Male Fern remove successively the bases of the leaves of previous 

 years, those of the current year, and finally the larger circinate 

 leaves, which would have unfolded in the following year. Care- 

 fully remove the smaller ones with a scalpel, and then with 

 forceps gradually pull off the large mass of brown scales, which 

 completely cover the extreme apex. With a stiff camel's-hair 

 brush remove the bases of these scales, together with the 

 youngest of them, which will still remain 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. 



X. With a sharp razor, wet with water or with very weak 

 spirit if the material be fresh, or with strong 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 immediately sur- 

 rounding it are arranged in more regular order than those at a 

 greater distance. This cell is the apical cell, and the cells 

 surrounding it have been derived by cell-division from it, by 

 mean of walls parallel to its three sides : they are called the 



