190 FLORA OF LOWER COAL MEASURES OF MISSOURL 



or where the bases of tlie leaves are reflexed or comjDressed downward. 

 Sometimes, however, it is nearly even, or appears rarely slightly emarginate, 

 in which case the profile of the vascular trace stands out more strongly in 

 the arch of the inward curve that marks the attachment of the lower side 

 of the leaf. Frequently, where the leaf bases were directed upward, the 

 compressed specimens show both edges of the scar as fairly even curves. 

 The latter are always very close, so that the broken epidermis of the upper 

 and lower surface of the leaf appears as a single line on the outer sides 

 beyond the appendages. Even in the central portion of the scar I have not 

 been able to find more than a very small transversely rhomboidal trace, such 

 as is seen in PI. LIII, Fig. Irt, the vertical diameter of which seems to be 

 no more than that of the midi'ib of the leaf. In all the specimens of this 

 easily distinguished species, including the types and other specimens from 

 Henry County, Missouri, identified by Professor Lesquereux and now in 

 the Lacoe collection, the leaf scar is of the same form. The examination 

 of the original of fig. 1, pi. Ixiii of the Coal Flora, shows clearly the cres- 

 centic line, which describes a rather larger arc than is indicated in fig. la. 

 The latter figure, too, conveys a better idea of the transvei'se corrugations 

 which diminish and vanish some distance below the leaf scar. Although in 

 portions of the originals and in jnany of the specimens collected later the 

 epidermis of the bolster is excellently preserved, I have not been able to 

 discover in a single bolster a line of separation or epidermal fracture which 

 can be consti'ued as marking a lower border of the leaf scar. The somewhat 

 indefinite lines marked in portions of fig. 2, loc. cit., are merely convention- 

 alized and extended from the uppermost, short, faint, corrugations of the 

 lower field. Here, too, a similar liberty is taken in introducing a central 

 point in several of the supposed leaf scars, though generally only the two 

 subcicatricial appendages are shown. The appendages are made to come 

 within the scar by the false lower boundary of the latter. These features 

 are not introduced in figs. 1 , la, and Ih, of the Coal Flora, unless the singular 

 curved line in fig. lb may be so interpreted. On the other hand, in most of 

 the fragments, including some of considerable size, in which the leaves are 

 preserved still in union with the bolsters, the union of the lower surface of 

 the leaf to the bolster is clearly seen to be along the upward-arching line 

 described above. The true position and attitude of the oval or oblong- 

 respiratory appendag'es are shown in the lowest bolster in fig. la. 



