[MATTHEW] FLORA OF THE LITTLE RIVER GROUP NO. II 97 



WHTTTLESEYA, Newbeny, 1853. 



Prof. J. S. Xewben-y described some peculiar leaves from the Coal- 

 measures of Ohio, wliich by some authors have been referred to Nœg- 

 gerathia, these do not display the flabellate growth of the leaf of 

 that form, but have parallel nerves. î^ewberry's description of the genus 

 was as follows: — 



Frond simple or pinnate, nerves fasciculate, confluent to the base, 

 not dichotomous ; fructifications unknoicn. 



The leaves of these plants are said to be " thick, narrowly fan-like, 

 truncate, undulate or dentate at the upper border, entire at the sides, 

 rounded in [and] rapidly narrowing to a short petiole; the nerves paral- 

 lel, composed of bundles of thread-like, simple filaments converging at 

 the base ; [these bundles] are separated by linear, smooth intervals." ^ 



Since Newberry's publication of the genus quite a number of related 

 forms have been added chiefly by Lesquereux and David White, the 

 latter of whom has elaborated the description of the genus to cover these 

 additions and who presents it in the following words: — 



" It embraces a type of narrowly petiolate leaves, more or less fla- 

 belliform in plan, whose nervation is composed of broad and thick, closely 

 or even densely arranged, fascicles or bands of nerves, originating chiefly 

 from a marginal strand on either side of the base, and sometimes fork- 

 ing not far above the point of origin before passing upward, longitudin- 

 ally parallel, to the generally truncate apex, where the nerves of each 

 band or fascicle abruptly converge in a more or less distinct crenulation 

 or tooth/' 



" The leaves may be oblong, squarrose, triangular, cuneate or linear. 

 They are always narrowed, sometimes so abruptly as to give an almost 

 round-truncate profile at the base. The petiole is usually long and often 

 filamentous. The lateral borders are in most instances nearly parallel, 

 and the distal border is frequently acutely dentate. In the more cuneate 

 forms the basal marginal nerves are less developed, the nerve fascicles 

 radiating more directly from the summit of the petiole. In some species, 

 and circumstantially in others, the vascular bands coalesce and are so 

 densely arranged in the thick leaf substance as to be hardly separable. 

 In most species the thickened central portions of the bands produce low 

 costae, though the bands are not wholly distinct from one another below 

 the teeth ;• or, in many examples in which the teeth or corrugations are 

 obscure, they may not be distinguished, unless topographically, for a 

 portion of their length. The bands sometimes divide once near the base. 



1 Coal Flora of Penn., p. 523. 



Sec. IV.. 1909. 7. 



