288 PRACTICAL BOTANY 



repeated bifurcation of the stronger nerves. On the 

 under side of the pinnae will frequently be found 



c. Sori, which are roundish brown groups of small 

 stalked bodies (sporangia), covered by a kidney-shaped 

 indusium. 



ii. The bases of the leaves of previous years will be 

 seen, covering the lower part of the stock or stem 

 externally : observe that lateral buds are frequently 

 to be found connected with these, being attached to 

 their ab-axial side, near to their point of junction with 

 the stem. 



iii. Nearer the apex of the stem than the expanded 

 leaves of the current year, and completely covering it, 

 are young leaves, densely covered with ramenta : 

 these, together with the axis, constitute the apical 

 bud. Note that the apex of each such leaf is rolled 

 up like a crozier (circinate vernation). 



Here, as in most Ferns, the development of the leaves 

 is very slow : the young leaves seated round the apex 

 represent the foliage-leaves of the two succeeding 

 years. 



C. The roots are rather thin and brown, with 

 transparent apices : they are inserted on the bases of 

 the leaves, close to their junction with the stem : the 

 branching of the roots is monopodial, and their branches 

 appear in acropetal succession. 



The stem of Aspldium Filix-mas does not branch at its apex : 

 the same is normally the case in the erect stems of Ferns (e.g. Tree- 

 Ferns) where the leaves are closely crowded. In those Ferns in 

 which the axis is elongated, a terminal branching is more frequent : 

 thus in Pteris aquilina there is occasionally a dichotomous branch- 

 ing. In other forms the new axes appear in connection witli the 



