266 MR MAC VICAR on the Germination of the Filices. 



those of the other individuals of this natural family ; and this 

 we may safely conclude of all those at least having prostrate 

 stems. The accompanying figures are representations of what 

 the author has observed in that species. In the explanation, no 

 dates are given, as the progress of germination depends entirely 

 on the age of the sporule, the supply of moisture, temperature, 

 &c. which are the measures of the progress of vegetation rather 

 than of equal spaces of time. 



After seeing the observations in the Edinburgh Encyclopae- 

 dia, it occurred to me that the seed of the Filices must consist 

 chiefly of two cotyledons folded together, which, by the absorp- 

 tion of moisture, and the germinating power, resolved themselves 

 into the forms represented by the author of that article ; an idea 

 in which I was confirmed by observing the sporule of Polypo- 

 dium vulgare, which appeared under a high magnifier curiously 

 folded together like the surface of a brain. Whatever the sur- 

 face of a sporule may be, however, the idea that it consists of 

 two folded cotyledons is altogether erroneous. The opinion of 

 GARTNER, that the testa of the seed is in them as well as in the 

 Musci and Fuci, totally occupied by what he terms vitellus, seems 

 much nearer the truth. The evolution of the Musci, indeed, has 

 so many points in common with that of the Filices, as to indi- 

 cate a similar structure of the sporule. HEDWIG, and, after him, 

 Mr DRUMMOND of Cork *, when observing the young shoot from 

 the seed of Funaria hygrometrica, saw that it had ruptured the 

 integument, which, until more extensive experiments be made, 

 may be considered as an epidermis. But whether this coat be, 

 as in the higher vegetables, an integument of a different struc- 

 ture from the enclosed parts, and existing previously to the ac- 

 tion of atmospherical causes, or whether it be a natural change 



* LIN. Trans. Vol. xiii. Part 1. 



