414 On Archjeopteris hibernica, Forbes. 



Schimper, is inadmissible, having been previously used by 

 Geinitz for a different group of plants. 



Among the Canadian species described by Dawson the 

 point of chief interest to us is the figure and description of the 

 fruit of Archceopteris (j/asjnensiSy a very closely allied species, 

 if really distinct from Archceojjteris kibertiica, Forbes, sp. 

 His description of the fruit is as follows : — " Fertile pinnse 

 with about twelve pinnules, each having a long midrib with 

 about seven pairs of crowded oblong spore-cases about 3 

 uiillim. in length, pointed or somewhat obtuse at top, straight 

 at the sides, and apparently dehiscent at the apex. The 

 midrib projects some distance beyond the spore-cases." It is 

 further mentioned that Archceopteris gaspiensis " differs from 

 A. Mhernica in the arrangement and form of the spore-cases 

 and in its shorter pinnae, with fewer and less obtuse pinnules"*. 



Since examining the specimens of Archceopteris hibernica 

 in the British Museum I have doubted the accuracy of the 

 description of the fruit of this fern as given by Schimper 

 and Carruthers, but refrained from expressing any opinion 

 till I had an opportunity of examining the specimens of 

 this plant in the collections of the Science and Art Museum, 

 Dublin, and of the Geological Survey of Ireland. I have 

 now examined these specimens, and feel convinced that the 

 description of the fruit as given by Schimper and Carruthers 

 is inaccurate. I have entirely failed to observe the presence 

 of a keel on the sporangia, as figured by Schimper, or the 

 occurrence of a " slit passing one third of the way down the 

 sorus," or any of the other Hymenophyllaceous characters 

 mentioned by Mr. Carruthers. The sporangia (so far as my 

 observations have gone, and I have examined minutely the 

 specimens in the British Museum, as well as those in the 

 two collections in Dublin, the finest of which are in the col- 

 lection of the Geological Survey of Ireland) are narrow-oval, 

 sessile, or very shortly stalked, as a rule pointed at both 

 extremities, though occasionally blunt; they are usually 

 developed singly, though occasionally in pairs, and are appa- 

 rently produced on the upperside of the rachis-like vein of 

 the very much metamorphosed pinnules, which in this case 

 almost assume the structure of pinnae, though their being 

 only modified pinnules is proved by their position and by 

 the occasional occurrence of a few sporangia on the margin of 

 some of the foliage-pinnules, which, in the few such cases 

 observed, had undergone but little reduction in the limb of 

 the pinnule. A similar production of sporangia on the 



♦ Dawson, /. c. p. 99. 



