CRYPTOGAMOUS PLANTS. 223 



Algae, and it seems to be one of the constant characters 

 of these plants; the Sporangia are sometimes so small, 

 as to be taken for simple seeds, and the error is the 

 more easy, as they seem to germinate when placed upon 

 earth ; at other times they have been confounded with 

 the grains of pollen. 



The most certain means of avoiding this last error, is 

 to observe the series of phenomena as well as their form. 

 The function of male organs is limited to the period of 

 fecundation, and it is observed in all known plants, that 

 the stamens perish after the emission of the pollen, and 

 usually fall off in a short time ; the female organs, on 

 the contrary, which have been fecundated, then com- 

 mence a new series of phenomena ; they increase in size, 

 become firm and opaque, and thus declare their true 

 nature. This system, simple, and founded at once upon 

 observation and reason, will enable us to recognise the 

 nature of the different powders which are observed in 

 the Cryptogamae: the more fugacious will be considered 

 as the male organs, the more lasting as female. We now 

 proceed to examine, in a general maimer, the structure 

 of the different families. 



Section II. 



The EquisetacecE. 



We have seen, (Vol. I. p. 200,) on speaking of the 

 structure of the Equi^etaeea?, that their branches and 

 the scales, the union of which formed their sheaths, are 

 verticillate around the axis. This disposition is also met 

 with in their organs of fructification. Their stems, and 

 often their principal branches, terminate in an oval or 



