THE CRYPTOOAMIA OR FLOWERLES8 PLANTS. 



129 



antheridia (as pollen?) and actively floating until they reach the arche- 

 gones, or perish. 



634. ALTERNATE GENERATION is a phenomenon distinctly traced in many of the 

 cryptogams. Thus the mosses, in germinating, first produce long, greenish fila- 

 ments quite analogous to the Confervas (frog's-spawn). From these, at length, buda 

 arise and grow into a true moss. Ferns, also, and Equisetacese, first from the spore 

 exist in tho form of a liverwort a small green thallus, creeping and rooting along 

 the ground. Secondly, upon this prothallus reproductive organs are developed and 

 an embryo, whence a true fern arises. Thus the plant is transiently, as it were, a 

 liverwort, permanently, a fern. (21 23.) 



635. OTHER MODES OF PROPAGATION occur in these plants, as, for example, by 

 innovations, sporules, gonidia. These bodies are analogous to bulbs and bulblets 

 in the flowering plants, originating from the nutritive organs, and capable of sepa- 

 rating from the parent and growing up independent planta. 



654 555 556 557 



552, Zoospore of one of the Conferva (Chaetophora). 553, Phytozoiin of Chara. 554 Anthe- 

 ridium of Fucus containing two phytozoa. 555, Zoiisporo of Confervas with a tuft of ciliiE. 556, 

 Another species with but two ciliae. 55T Zoiispore of Vaucheria with cilia all around. 



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