384 equisetacejE :— movement of spores. 



instantaneously put in motion, thus presenting an extremely 

 curious spectacle ; and will almost as suddenly return to their 

 previous condition when the effect of the moisture has passed off. 



Fig. 196. 



Spores of Equisetum, with their Elastic Filaments. 



If one of the Thecce which has opened, hut not discharged its 

 Spores, he mounted in a slide with a movable cover (§ 155), 

 this curious action may he exhibited over and over again. These 

 spores are to be regarded in the same light as those of Ferns, 

 namely, as Gemma or rudimentary Buds, not as seeds. They 

 evolve themselves after the like method into a Prothallium ; and 

 this developes Antheridia and Archegonia, by the conjoint action 

 of which an Embryo is produced. 



I *282. In ascending, as we have now done, from the Lower to the 

 Higher Cryptogamia, we have seen a gradual change in the general 

 plan of structure ; so that the superior types present a close 

 approximation to the Flowering Plant, which is undoubtedly the 

 highest form of Vegetation. But we have everywhere encountered 

 a mode of Generation, which, whilst essentially the same through- 

 out the series, is essentially distinct from that of the Phanero- 

 gamia ; the fertilizing material of the Sperm-cell being embodied, 

 as it were, in self-moving filaments, which find their way to the 

 Germ-cells by their own independent movements; and the Embryo- 

 cell being destitute of that store of prepared nutriment, which 

 surrounds it in the true Seed, and serves as the pabulum for its 

 early development. In the Lower Cryptogamia, we have seen that 

 the Embryo-cell, after fertilization, is thrown at once upon the 

 world (so to speak) to get its own living ; but in the Liverworts, 

 Mosses, and Ferns, the Embryo-cell is nurtured by the parent-plant, 

 for a period that varies in each case according to the nature of the 

 fabric into which it evolves itself. While the true reproduction 

 of the species is effected by the proper Generative act, the multi- 

 plication of the individual is accomplished by the production and 

 dispersion of Spores ; and this production, as we have seen, takes 

 place at very different periods of existence in the several groups, 



