HISTORY OF BRITISH FERNS. 



to support the application of such names to the parts, at 

 least in their ordinary signification. It seems more pro- 

 bable that the larger bodies are the perfect spores, while the 

 smaller ones are merely abortive spores ; at least this is the 

 most reasonable explanation which has been offered. There 

 is, indeed, no doubt of the larger bodies being spores, since 

 they have been caused to germinate by different persons, 

 and a very detailed record of some experiments and observa- 

 tions on this subject has been given by Mr. Valentine. 



According to Mr. Valentine's observations, the first ex- 

 ternal sign of germination is either the appearance of four 

 cells projecting through the apex of the nipple-like point of 

 the spore, or a gradual swelling of that part, in which case 

 the enlarging cellular mass distends the conical point, and 

 at length appears externally with four of its cells projecting 

 beyond the general mass, and compressed into a quadran- 

 gular form. Soon after the exposure of the entire germ, 

 little rootlets shoot out from one side ; they are simply ar- 

 ticulated tubes, or elongated cells applied end to end. The 

 germ now gradually points in two places, which points gra- 

 dually lengthen, and each on dissection is found to consist 

 of a closed sheath, one containing a leaf, the other a root. 

 The young leaf, when rather longer than the spore, bursts 



