STlltJCTURE OE EERNS. 



7 



like manner; but, if examined, the structure will be found 

 precisely similar, on a larger scale, to the root-stock of 

 our common Male Eern : that is to say, the stem is com- 

 posed of the bases, or lower portions, of the old stipes 

 which have decayed and fallen away year by year, as new 

 fronds have consecutively grown at the summit, to die and 

 fall away in their turn, and leave the lower portion of 

 their stipes as a contribution towards lengthening the 

 stem of the fern. Hence it will be evident that neither 

 the root-stock of the Male Eern nor the stem of the tree- 

 fern at all resemble the stem of a shrub or the trunk of a 

 tiee, and it is, in fact, only an elongated root-stock, 

 scarcely meriting the name of a stem. 



Erom the under side of the root-stock when creeping, 

 and from all sides when erect, the tough fibrous roots 

 descend into the soil. These are the true roots. There 

 are various modifications in the form of the root-stock, 

 which may be studied and compared with advantage in 

 the common Bracken, the common Polypody, and the 

 Male Eern. 



It may be observed here that the vascular bundles of 

 the stipes of ferns furnish the scalariform tissue so well 

 known to microscopists, to obtain which for microscopical 

 examination the following method has been recommended: 

 " The fern stipes, cut into short lengths, should be boiled 

 in a solution of caustic soda (about thirty grains to the 

 ounce of water) for a quarter of an hour or so ; then take 

 them out and crush them well in a mortar, replace them 

 in the solution, and boil again for five or ten minutes, 

 when they will be found to have become quite soft, the. 

 cuticle can then be picked out and thrown away. Allow 

 all the fine fibres to settle, pour off the dark-coloured fluid, 

 and boil them three or four times in water, adding to the 

 last water a few drops of hydrochloric acid, which whitens 

 the mas-s considerably. On crushing a little of this fibre 

 in a ^Lve-box,' the scalariform ducts may be easily seen, 

 their position noted, and, on removing the cover, picked 

 out. The ladder-like markings are be-st seen when 

 mounted in fluid." 



