354 MB. C. T. DBUEEY ON A SINGULAR MODE OF 



Observations on a singular Mode of Development in the Lady- 

 Fern (Athyrium Filix-foemina). By Cha.bles T. Dbu¥ev\ 

 (Communicated by Dr. J. Mueie, F.L.S.) 

 [Eead 19th June, 1884.] 



TnE reproduction of the Filices by tbeir spores results from 

 sexual action taking place upon the under surface of the 

 prothallus to which the spore gives rise. So far, I believe, no 

 development of the perfect prothallus has been observed with- 

 out the agency of the spore, and the following record of such 

 a case therefore deserves special notice. 



Some years ago a very distinct and beautiful form of Atliyrium 

 Filix-foemina was found wild by Mr. Moule in North Devon, 

 from whose possession it passed into that of Col. Jones, of 

 Clifton. Many attempts were made at the time to propagate 

 it from what were assumed to be spores, always, however, 

 without success ; and at length it was taken for granted that the 

 peculiar growths produced by this Pern in the place of sori were 

 n erely abortive spore-cases, and that the plants, like some other 

 abnormal forms, lacked the special vigour necessary for the for- 

 mation of perfect reproductive spores. All further attempts at 

 raising it were consequently abandoned ; and only two divisions 

 of the plant exist *. In the autumn of 188tS I discovered upon 

 another Atliyriuin {A. F.-f.,\a,r.plumosum divariccttum) numerous 

 proliferous bulbils occupying the place of sori on the back of the 

 fronds ; and, reporting this to Mr. Gr. B. "Wollaston, he was led to 

 re-examine A. F.-f. clarissiina, as the Fern in question had been 

 named by Col. Jones, and came to the conclusion that these so 

 far barren excrescences might be viviparous growths of a kindred 

 nature, and capable of reproducing the parent form by direct 

 bud-development. A portion of a frond was consequently sent 

 to me, and upon examining it under the microscope I found that 

 there were very material structural differences between the 

 unmistakable bulbils of A. F.-f. divaricatum and the singular 

 growths upon A. F.-f. clarissima, the former being solitary bud-like 

 growths seated in the centre of a number of brown lanceolate scales 

 and without a trace of indusium; while the latter were com- 



* It is, of course, open to question whether the excrescences formed prior to 

 1883 were of exactly the same nature. Col. Jones inclines to the belief that 

 they approached more nearly the character of sori, and did not in previous 

 years present the same appearance as now described. 



