ORGANS OP FLOWEELESS PLANTS. 97 



2. The formation of the germ-tube, as in Mucorini, or a 



promycelium with sporidia, as in the teleutospores 

 of Uredinese, the early stages of growth of the pro- 

 toneina of Muscinese and the prothallia of vascular 

 cryptogams. 



3. Peculiar phenomena, such as the formation of zoo- 



spores of the Peronosporese ; and 



4. Observations of the vitality of spores under natural 



conditions of temperature, etc., and also when 

 exposed, to artificial media. 



In all but the highest cryptogams the phenomena stand 

 in marked contrast with the germination of flowering 

 plants, which consists essentially in the development of a 

 previously formed embryo. 



III. Vegetative Growth of Cryptogamic Plants. This may 

 have the form of (1) single cells, as in the case of yeast, 

 many moulds prior to fructification, and many algse ; and 

 (2) tissues. The latter may be merely septate filaments, as 

 in Spirogyra and many simple algse, or there may be more 

 expanded thalloid growth, as in other algse, in the liver- 

 worts, fern prothallia, etc., or there may be a more or less 

 erect, leafy plant, as in the mosses and vascular crypto- 

 gams, the tissues in the latter showing a high degree of 

 differentiation. As peculiar vegetative growths, hardly 

 belonging in strictness to either of the above categories, 

 may be included rhizomorphs and various other forms 

 assumed by the mycelium of fungi. 



The nutrition of the vegetative body suggests a com- 

 parison of the fungi, destitute of chlorophyll, with algse, 

 mosses, and other plants that contain it, and the conse- 

 quent extreme difference of habit, manifested in the inde- 

 pendent life of the latter and the parasitism or saprophytism 

 of the former. Connected with the same subject is that of 



