[MATTHEW] FLORA OF THE LITTLE RIVER GROUP NO. II 85 



space on the rachis. Also I have not found a large terminal leaflet; on 

 the contrary the pinnules or leaflets become shorter and smaller toward 

 the tip of the pinna. 



Sir William makes no allusion to the fruit of this species, but if it 

 were an Alethopteris and we accept the definition of the early palseo- 

 botanists, we would expect to find the fructification marginal, borne 

 under the reflexed margin of the pinnule, as in Pteris ; but though I have 

 handled hundreds of examples of these pinnules 1 have found none in 

 which the fructification is so situated; on the contrary all the pinnules 

 are entirely free of any appearance of sori. 



The reason is seen in the variations in the growth of the narrow 

 pinnules and their association, with and passage into peduncular shoots. 

 An inkling of this modification is given in one of the examples figured 

 by Sir William in the last and most complete account which he has given 

 us of the remarkable flora to which this species belongs. This example 

 will be found in Plate XVIII, fig. 205, of this memoir ;i it will be noticed 

 that at the termination of this pinna we do not have the large pinnule 

 which Sir William's diagnosis would place there, but a slender rachis, 

 and a weak and distant pinnule. In several examples which I have seen, 

 this rachis becomes entirely devoid of pinnules and extends into a long 

 slender peduncle, garnished at distant intervals by groups of the bracts 

 of Sporangiies acuminatus Dn. We thus seem to have this fossil con- 

 nected to Alethopteris discrepans as its fruiting portion. 



Sporangites acuminatus occurs with vegetative parts of other Ferns 

 and Pteridosperms. That it should be found with the ubiquitous Nev^ 

 ropteris polymorpha and Asierocalamites scrohiculoides is not surprising, 

 but it is also found on the same surfaces as Hymenophyllites (3) Cal- 

 lipteris? (3) Pecopteris (1) Cordaites (2) Neuropteris sp. (1) These 

 plant-remains are, however, only occasional in their occurrence with 

 Sporangites acuminatus; and on the surfaces where they occur the pin- 

 nules of Alethopteris discrepans are invariably present, viz : broad form 

 (5), intermediate form (6), narrow form (15). 



The figures in brackets show the frequency of occurrence on about a 

 score of slab-fragments of the shale, and the last named form it will be 

 seen far outnumbers the others. This, however, is not all, for on a num- 

 ber of otheï examples where A. discrepans and S. acuminatus occur to- 

 gether, the latter is found in three quarters of the occurrences with the 

 narrow form of ;the former, hence it is more nearly related to the narrow 

 form than to the broad or the typical form of these leaves. 



To take up now the fruit of this Pteridosperm, one may first relate 

 what Sir Wm. Dawson has said about it. 



1 Fossil Plants of the Devonian and Upper Silurian formations of Canada. 



