352 MICROSCOPIC STEUCTURE OF HIGHER CRYPTOGAMIA. 



both are obliterated, so that there is no peristome at all. The 

 number of the "teeth" is always a multiple of 4, varying from 4 

 to 64 ; sometimes they are prolonged into straight or twisted hairs. 

 The spores are contained in the upper part of the capsule, where 

 they are clustered round a central pillar, which is termed the 

 columella. In the young capsule, the whole mass is nearly solid 

 (Fig. 135, c), the space [1) in which the spores are developed 

 lieing very small; but this gradually augments, the walls be- 

 coming more condensed ; and at the time of maturity, the inte- 

 rior of the capsule is almost entirely occupied by the spores, in 

 the dispersion of which the peristome seems in some degree to 

 answer the same purpose as the elaters of HepaticEe. The deve- 

 lopment of the spores into new plants, commences with the rap- 

 ture of their outer walls, and a protrusion of their inner coats; 

 and from the projecting extremity new cells are put forth by a 

 process of outgrowth, which form a sort of confervoid filament 

 (as in Fig. 145, c). At certain points of this filament, its compo- 

 nent cells multiply by subdivision, so as to form rounded clus- 

 ters, from every one of which an independent plant may arise; 

 so that several individuals may be evolved from a single spore. 

 A numerous aggregation of spores may be developed, as we have 

 seen, from a single germ-cell; so that the immediate product of 

 each act of fertilization does not consist (as in the higher Plants) 

 of a single seed, that afterwards developes itself into a composite 

 fabric, whence are put forth a multitude of leaf buds, every one 

 of which is capable (under favorable circumstances) of evolving 

 itself into a complete Plant; but divides itself at once into a 

 mass of isolated cells (spores), of which every one may be con- 

 sidered in the light of a bud or gemma of the simplest possible 

 kind, and one of the first acts of which is to put forth other buds, 



whereby the rapid extension of these 

 Fig. i4n. plants is secured, although no separate 



individual ever attains more than a veiy 

 limited size. 



218. In the Ferns we have in many 

 respects a near approximation to 

 Flowering plants; but this approximar 

 ; j^ tion does not extend to their Eeproduc- 

 tive apparatus, which is formed upon a 

 type essentially the same as that of 

 Mosses, but is evolved at a very different 

 period of life. As the component tis- 

 sues of which their fabrics are com- 

 posed, are essentially the same as those 

 Oblique seciio.i of footstalk of Fern- -which wiU bc dcscribed in the next chap- 



Ufif, showing bundle of scalanform . ., .,, , , . ., , , j ^^ll 



ducts. ter, it will not be requisite here to dwell 



upon them. The stem (where it exists) 

 is for the most part made up of cellular parenchyma, which is 

 separated into a cortical and a medullary portion, by the inter- 



