THE CRYPTOGAMIA OB FLOWERLESS 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 Equisetaceae, first from the spore 

 exist in the form of a liverwort a small green lhallus, 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. OTHEE MODES OP 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 plants. 



552 553 554 555 556 55T 



552, Zoospore of one of the Confervas (Chaetophora). 553, Phytozoon of Chara. 554; Anthe- 

 ridium of Fucus containing two phytozoa. 555, Zoospore of Confervas with a tuft of cilice. 556, 

 Aaother species with but two ciliae. 557 Zoospore of Vaucheria with cili all around. 



9 



