DESCRIPTION^ OF SPECIES. PP. 45 



and more complex in division than the rest, and deilexed 

 along the secondary racliis, incisely lobed, with the divi- 

 sions bluntly toothed, slightly decurrent on the tertiary 

 rachis, and becoming united towards the end of the pinnge ; 

 primary nerve of the pinnule, strong and somewhat tiexu- 

 ous, giving off nerves which l)ranch palinately into the 

 rounded, slightly marked lobes of the pinnules, a branch 

 passing into each of the crenate teeth of these lobes. 



The ultimate pinnae, or pinnules, at the lower part of 

 the secondary pinna^, are so much larger and deeply cut 

 than the rest, that in them the plant is quinquepinnatifid at 

 least. The tertiary pinnae near the base of the secondary 

 ones, are shorter than the normal ones, and have contracted 

 pinnules, whose nervation is distorted somewhat, and 

 shows a tendency to inflation, as if this portion of the plant 

 might become fertile, but no fructification can be made 

 out. The dwarfing of this portion of the pinnse, is con- 

 trary to the rule, as w^e find generall}^ that the length of 

 the pinnee diminish from the base to the summit of the 

 rachis which bears them. Another of the curious features 

 of this plant is the marked heteromorphism and deflexed 

 position of the basal pinnules on the lower side of the 

 pinnge. The pinnules on the loAver portion of the pinn?e 

 are slightly decurrent, and united each by a narrow wing- 

 to the next lower, while towards the summit they are more 

 and more united. The value of the peculiar dwarfing of 

 the lower portion of the secondary pinnae we cannot determ- 

 ine, as we found only one specimen showing this part of 

 the frond. It may be specific. It will be observed that 

 this iDortion is preceded by a pair of large complex pinna3, 

 such as we might expect from their position, which is next 

 to the primary rachis. 



This plant, wdiich is one of the finest in the entire Carbon- 

 iferous flora, is beautifully preserved in the fine grained 

 shale, on which it is found, and every detail can be easily 

 made out. Its affinities seem to be with Pecopteris cris- 

 tata, Brongt., which it resembles in some points, and it evi- 

 dently belongs to the Pecopteroid section of the Sphenoji- 

 terids. 



