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Liver-mosses; or the cell expands into a longish utricle or tube, but 

 only one extremity of this tube becomes filled with cells, which gra- 

 dually grow up into a new plant, the remaining portion of the cell, 

 meanwhile, decaying ; this is the case in the remaining Liver-mosses, 

 the Mosses, Ferns, Lycopodia and Equiseta. * * In all these 

 Cryptogamia the reproductive cells are called spores, or germinal 

 grains." — p. 70. 



In the Phanerogamia, or flowering plants, the operations of repro- 

 duction and germination are much more complicated. The repro- 

 ductive cells are called pollen, and are formed in those peculiar 

 modifications of leaves called the stamens. Here, instead of at once 

 falling to and germinating upon the ground or in the water, the cells 

 require the intervention of the reproductive apparatus known as the 

 ovary, style and stigma. In the hollow part of this apparatus, named 

 the ovary, are little protuberances formed of cellular tissue, — the 

 seed-buds or ovules, and in each of these is a large cell, or the em- 

 bryo-sac. 



" At the flowering period the pollen falls upon the stigma, and then 

 commences the development of the reproductive cells. Each one 

 extends itself into a long filament, exactly as in the Cryptogamia, 

 and in this form penetrates to the cavity of the germen, to enter one 

 of the seed-buds, and finally, into the embryo-sac. The extremity 

 which has passed in now becomes filled with cells, and these deve- 

 lop forthwith into a perfect, though as yet simple and minute plant- 

 ule, the so-called embryo or germ. Simultaneously with the deve- 

 lopment of the pollen-cell into the embryo, the seed-bud is perfected 

 into a seed, the germen into the fruit. A pause in the growth now 

 suddenly occurs, and the seed may often be preserved for a long time 

 in this apparently dead condition. But when favourable external 

 circumstances come into play, the life begins anew with the further 

 unfolding of the plant, which is commonly called germination." — 

 p. 71. 



Such is, in fact, Schleiden's theory of the development of the em- 

 bryo in the ovule ; and we were long ago struck, long, indeed, before 

 we read anything which has been written upon the subject, with the 

 analogy between pollen-grains and spores — between anther-cells and 

 the thecae of ferns : and it is but a step further in the same direction 

 to conceive the same analogy to obtain also between the first act of 

 germination of a spore upon the ground or in the water, and the de- 

 velopment of an embryo from a pollen-grain in the embryo-sac of an 

 ovule. This latter process, it is true, is not germination : but it is a 



