1 6 PARTS OF FERNS. 



too. When an involucre grows out beneath a sorus, and its edges, after rising round 

 the outside of the sorus, meet above and enclose it, it is said to be " inferior" ; but if 

 it from the first appears above the sorus and covers it, and thus the capsules grow out 

 from under its edges, it is said to be " superior." Sometimes it is necessary to examine 

 fronds at different stages of growth, as a scale-like involucre, which completely covers 

 and protects the young capsules, is often buried and lost sight of among them as they 

 attain maturity. In some cases, too, there are hairs intermixed with the capsules. 

 Capsules are usually surrounded by an elastic ring, which causes them to burst open 

 when ripe so as to shed their spores ; the manner in which the capsules open being 

 another means of identification. In the various classes of ferns the sori are " de- 

 pressed," " inserted," " exserted," " sessile," or " stalked," so that there are plenty of 

 clues to the identification of a plant if one will only take the trouble to use them, and 

 to those who will do so the study soon becomes extremely .interesting. One of the 

 most curious things that can be shown to children is the following : Get a nearly ripe 

 frond of a fern, or piece of a frond of a tree fern, and let it lie on a sheet of paper till 

 the capsules burst and shed their spores, which look like brown dust. On looking at 

 this dust through a magnifying glass it appears alive, the rings which have burst the 

 capsules and then become detached from them coiling and uncoiling like animated 

 watch springs and jumping about like cheese hoppers. This action, occurring naturally 

 on the growing frond, scatters the spores abroad, just as the sudden bursting and 

 curling of the ripe pods of gorse, peas, broom, balsams, &c., scatters their seed 

 to a considerable distance. I know nothing more calculated to impress on a 

 child's mind that there is actual life in a plant than seeing these rings moving of 

 themselves. The term " hairs" explains itself ; but " scales" are hairs with flattened 

 bases, of greater or less width ; and these, when of a light brown or straw-colour, 

 are said to be " chalTy." When long, narrow, tapering to a sharp point and slightly 

 bent, they are called " subulate," from the Latin word subula, a shoemaker's awl. 

 Hairs and scales are often connected to the frond by a sort of joint ; and in this 

 case generally fall off after a while, as the frond ripens, in which case they are 

 said to be " deciduous." Sometimes, too, they get darker in colour as the frond 

 matures ; so my readers must not be misled by an apparent difference, in this 

 respect, from the description. A part of the leafy portion of a frond continued 

 along the rachis or a midrib is called a " web" or " wing." The texture of a frond 

 may be either " membranous," " filmy," or " diaphanous," when thin and trans- 

 parent ; " herbaceous" when soft, opaque, and bright-coloured ; or " coriaceous" 

 when tough and leathery-looking. " Glabrous" is shining or polished ; " hispid" 

 bristly, " hirsute" having soft hairs, "villous" or "pubescent," downy; and "pilose" 

 having a few hairs. Anything on the upper side of a frond is said to be " superficial" ; 

 .anything on its edge " marginal" ; on the ends " terminal" ; and on the back " dorsal." 



