SECTION III. 



PTERIDOPHYTA. 



Ferns. 



Ferns belong to the third subdivision of the Vegetable Kingdom the 

 Pteridophyta which also includes the Horse-tails and Club-mosses plants 

 which have no flowers, in the ordinary sense of the word, and therefore no seeds, 

 but are reproduced from spores. 



These spores axe contained in small cases on the edges and under side 

 of the fronds, the latter being the name given to that part of the fern which, in 

 flowering plants, we should call the leaf. 



This distinction of name serves to call attention to other characteristics 

 of these plants. 



Ferns have roots and stems, but not the whole of the plant which we find 

 beneath the ground is root. The true roots are always fibres which naturally 

 grow downwards into the soil ; the stem (rhizome) is frequently underground, 

 or prostrate upon it, and consists of a thick mass of tissue from which the stalks 

 of the fronds grow upwards, as the roots grow downwards. When above the 

 surface they are covered with scales and hairs, and appear very shaggy. In 

 the Common Bracken, however, the stem rises erect like that of a flowering 

 plant. This stem is worth examination. If you cut it through transversely, 

 you will find it to consist of cellular tissue, through which distinct bundles of 

 woody fibres run, generally darker in colour. Those of the bracken form a 

 rough horseshoe shape. This is one of the subjects which should be examined 

 in the microscope. 



The fronds vary very much in form, but all consist of a stalk (stipes) and 

 blade. In some cases as, for instance, the Hart's Tongue the blade is 

 undivided, entire; others are deeply divided. When the indentations do 

 not reach the midrib, the frond is said to be pinnatifid ; when they do reach 

 the midrib, thus forming a series of little leaflets, pinnate. These leaflets, if 

 cut again, are called bipinnate ; if a third time, tripinnate ; if still more, 

 decompound. 



The fronds are veined hi various ways ; the arrangement may be almost 

 straight and parallel, or forked. 



Another point of interest is that when the fronds are first formed in the bud 



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