368 MR ROBERT KIDSTON ON THE FOSSIL FLORA OF THE 



Remarks. — This species is common throughout the whole of the Eadstock 

 area, but usually occurs in a fragmentary condition, seldom more than isolated 

 pinnae being met with. 



Many botanists regard Pec. emarginata, Gopp., sp. ( = Pec. longifolia, Brongt, 

 not Sternb.), as specifically distinct from Pec. unita, Brongt. ; on the other hand, 

 some regard them as only different portions of one species. 



I have carefully collected specimens of the plants that have been referred 

 respectively to Pec. unita, Brongt,, and Pec. emarginata, Gopp., sp., and com- 

 pared them with specimens of the latter species from Wettin, with which many 

 of the Eadstock examples agree, but have failed to discover any character by 

 which Pec. emarginata can be separated specifically from Pec. unita. They 

 seem to me so to pass into each other that their separation appears arbitrary, 

 and not determined by any fixed character peculiar to either form. 



A few specimens in fruit, identical with Weiss's figure of Stichopteris 

 emarginata { — Pec. emarginata, Gopp., sp.), have also been met with. 



For the satisfaction of those who may regard Pec. emarginata as a distinct 

 species, its distribution is given separately under the distinction of Pec. unita, 

 forma emarginata. 



Description of Specimens Figured. 



PL XXIV. fig. 3, Pec. unita, Brongt. ; from New Mills Pit {Farrington Series). 

 — This sketch shows the typical plant as figured by Brongniart in his Hist. d. 

 veget. foss., pi. cxvi. fig. 1. On the lower pinnae the pinnules are separate to 

 the base, but as the pinnae approach the apex of the specimen (which from the 

 inequality of the pinnae on the two sides of the rachis is evidently a pinna and 

 not the terminal portion of a frond), the pinnules become more or less united 

 among themselves, till on the uppermost pinnae the pinnules are so completely 

 united that the pinnae appear entire or only slightly dentate. At fig. Sa are 

 given two pinnules, enlarged 2 times, from a lower pinnae, to show the nerva- 

 tion. 



The veinlets are sometimes almost straight, but usually curved upwards 

 (as in fig. i)a), though occasionally curved outwards (as in fig. da). 



PI. XXIV. fig. 9, Pec. unita, Brongt. ; Camerton. — This figure shows the 

 pinnules united to each other for about two-thirds of their entire length. The 

 specimen is a portion of a primary (?) pinna nearer its base than that just 

 described (fig. 3), and corresponds to Brongniart's fig. 5, pi. cxvi. The veinlets 

 are curved upwards, — the two contiguous basal veinlets coalescing and extend- 

 ing to the base of the notch that separates the free portions of neighbouring 

 pinnules. This arrangement of the nervation — the union of the two basal 

 contiguous veins and the formation of a veinless triangle at the base and 



