246 On Azolla and Salvinia. 



plants very much differing in general organization, should 

 be found ; so I do not lay stress upon the possibility of the 

 elongation, just referred to, being reduced to such an al- 

 most inappreciable amount as might perhaps occur in a 

 Gymnospermous ovulum with exserted embryo sacs. 



A difficulty may also be considered to be presented by 

 the existence of the hairs round the base of the ovula. For 

 these in their structure resemble what I suppose to be the 

 male organs of Ferns, and also the anthers of certain Mosses 

 and Hepaticae ; although the terminal cell presents less gra- 

 nular matter than usual. 



In the respect of the supposed males, Azolla presents 

 greater analogies with phanerogamous plants, than either 

 Musci or Hepaticae, in which nothing analogous to pollen 

 grains has been, I believe, yet observed in the anther ; which 

 again can scarcely in all cases be considered a grain of pol- 

 len, the view suggested by the contents. Still even with the 

 objections before mentioned the analogies are as tenable I 

 think as those existing between the pistilla of Mosses and 

 of phanerogamous plants ; those organs in the former being 

 originally closed, in the latter, theoretically at least, original- 

 ly open. 



General objections may be raised from the fact of monili- 

 form filaments similar to those of Azolla having been found 

 on the capsule of Salvinia, unconnected apparently with fecun- 

 dation, and on the dissimilarity of the supposed fecundating 

 process in the two genera. 



These observations, although they appear to me to indi- 

 cate the existence of sexes in Azolla and (Salvinia) as strong- 

 ly as in Musci and Hepaticae, (in which they are admitted by 

 the best botanists), do not bear out in any way the ideas hi- 

 therto entertained by botanists regarding the sexual organs 

 of the two genera in question. For independently of the or- 

 gans being the same in structure up to a comparatively late 

 period, they are both submitted to the action of the same 



