97 



<®viginal .avticies 



ON SOME POINTS IN THE DEVELOPMENT OF 

 OSMUNDA liEGALIS, L.- 



By Charles P. Hobkiek, F.L.S. 



(Tab. 228.) 



The object of the following notes is to draw the attention of 

 botanists and fern-growers to some points in the development of 

 this fern, after the appearance of the first growth from the pro- 

 thallus — points which I have not seen previously noticed. My 

 attention was first given to these points by accident. I had 

 growing, in a window-case built outside my dining-room window, 

 a faii'-sized plant of Osmmida vfigalis, which cast its spores freely. 

 The window-case is a large one, some ten feet long by five feet 

 broad, and in one portion is a small pond with a fountain, the 

 spray from which keeps the plants well supplied with constant 

 moisture. About six years ago I noticed small young plants 

 springing from a prothallus close to the original plant. These 

 young growths were so unlike the then supposed parent that I 

 watched their development carefully, and have continued to do so 

 during the last six years ; and it is the result of this careful 

 watchmg to which I am desirous of calling attention. 



I have nothing to remark on the development of the spores 

 into the prothallus, and the first growth of the cells from the 

 fertilised archegonia, except that the production of antheridia with 

 me has been remarkably prolific. Dr. Kny has published an 

 elaborate paper on this early development in Pringsheim's 

 ' Jahrbuch,' vol. viii., and, so far as I can judge, my observations 

 commence about the stage at which he leaves off. The prothallus 

 has usually appeared about the month of February, and m about a 

 month or six weeks afterwards have appeared at its edges the 

 first young frondlets. This first frondlet is a small expansion of 

 cellular tissue, rarely more than one-eighth of an inch in diameter, 

 but in some few instances reaching a quarter of an inch. This is 

 supported on a thin seta about a half to three-quarters of an inch 

 in height. The leaf- like expansion is irregularly oval in shape, 

 either slightly lacerated or faintly crenate on the margin, and is 

 generally notched at that portion of the edge immediately opposite 

 to its junction with the footstalk, thus giving it a slightly lobed 

 appearance. The principal vein or midrib divides into two imme- 

 diately after leaving the footstalk, one branch turning to the right 



* Read before the British Association, at York, 0th September, 1881. 

 N. s. VOL. 11. [April, 1882.] o 



