A.20LLA AND SALVINIA. 



54/ 



though not confined to different capsules, in Isoetes and 

 Psilotum. And this, to which the dissimilarity of the mature 

 reproductive organs is mainly attributable, thus becomes so 

 general, that it obviously relates to something important, and 

 will probably be found to exist in particular portions of the 

 families just mentioned as exceptions. 



Mr. Valentine,* was so far as I know, the first who dis- 

 tinctly attributed this want of uniformity to abortion, an 

 opinion which appears to be correct to some degree at least. 



The anomaly observable in the numerous spherical pedi- 

 celled secondary capsules, througli the previously free spores 

 become enclosed in cells, which subsequently partly or en- 

 tirely coalescing form solid masses, in which the spores are 

 then imbedded, is, I think, very remarkable. 



The appearance, however of these cells, which exist in 

 both genera, and which seem to be developed from the inner 

 surface of the secondary capsules, either corresponding to 

 and enclosing several spores, or at least as in Salvinia 

 occasionally arising opposite single ones, is not organic: 

 it is that of the mammilla of the yellow sac. The young 

 masses indeed are like it elastic, and it is evident that there 

 is neither a common nor a partial membrane. 



It is difficult to believe that these masses are abortive 

 developments, particularly when the appearance of grume or 

 molecules in the imbedded spores, and the obvious hypo- 

 thetical capability of growth of the «nasses is considered. 

 Direct observation on this head is required and if it be 

 found that they do produce young plants, and that the 

 growths take place from more than one of the imbedded 

 spores, an analogy may become presented to pluri-embryonate 

 Gymnospermous plants. 



their subsequently containing granular matter, objections to this, thougir 

 none of them can be considered conclusive. Still it is not to be denied, 

 that if compared with the mature spores of Filices, Musci, Hepatite, 

 in all which the spores have hitherto been found uniform, they exhibit ai 

 apparently imperfect state of development. 



* Valent, Linn, Trans. 491, 497, t. 35, f. 34, 35, 3(3, 



