WHITE.] NOTES ON CHARACTERISTIC SPECIES. 891 



a little more distant, oblique, slightly polymorphous, though generally 

 ovate to oblong-ovate when small, becoming oblong and gradually 

 constricted at the base, the largest attached at the midrib, narrowed a 

 little toward the usually very unequal, obliquely rounded, asymetrical 

 base, the attitude and form a little variable, tapering somewhat in the 

 upper two-thirds, obtusely rounded or rounded at the apex, the termi- 

 nal often elongate-ovate, often nearly acute, the margins, as in the 

 largest pinnules, more or less distinctly sinuate; lamina thin, very 

 slighth" convex ventrally at the border; nervation thin, but very 

 distinct; midrib, when developed, becoming flexuose and vanishing in 

 the upper part of the largest pinnules; secondar}^ nerves a little dis- 

 tant, ver}' oblique, usually forking close to the point of origin, the 

 divisions forking twice or three times in passing to the margin, which, 

 even in the largest pinnules, they meet at varying degrees of obliquity. 



This variety presents certain phases which would appear to entitle 

 it to full specific rank, though the presence, at one point or another in 

 the Appalachian trough, of other forms showing every degree of transi- 

 tion or genetic connection renders its specific separation impracticable. 

 It afl'ords a fine illustration of unquestionable modification. Thus, 

 certain of the largest of the pinnules are less obliquely narrowed at 

 the base, more distinctly oblong, and even-margined. Such have in 

 our collections sometimes been confused with Neuropteris Informix 

 Lx., and accordingl}^ so recorded in the distribution of that really 

 Alethopteroid and very rare form.' The phase whose fragmental 

 (often detached pinnules) representatives have been the subject of this 

 error is somewhat characteristic of the middle portion of the Pottsville 

 series. 



Another variation, whii-h can be considered as onh" varietally or per- 

 haps formally distinct from the one in hand, is seen in the plants from 

 the Dade mines in northwestern Georgia, described and illustrated as 

 secondary types of JVewopteris SinithsU. ^ While the Dade plants show 

 an outline and habit hardly distinguishable from the variety in hand, 

 they reveal a rather coarser nervation, which is more open near the 

 midrib, often slightly flexuose, and usually a little more distant. A 

 comparison of the types, or even of figs. 1 and 2, pi. xiii, of the Coal 

 Flora, the originals of JV. SmitJisU^ with the illustration of the Dade 

 specimen, pi. xcvi, fig. 3, of the same work shows at a glance the 

 specified difi['erences in the fossils. The true Df. Smithsii has small 

 pinnules open at a right angle, quite constricted at the base, well 



iThe latter, as seen in examples from Alabama, some of which were identified by Professor Les- 

 quereux, have long, tapering pinnules, thiek. persistent midribs, strongly arched close nervation, the 

 terminal and preceding pinnules being almost typically Alethopteroid. These features, slightly 

 imperfectly shown in the Coal Flora (p. 121. pi. xiii, fig. 7) will later be more fully illustrated from 

 typical material. 



*Le.squereux, Coal Flora, Vol. Ill, p. 734, pi. xcvi, figs. 3, 3a. No. 1156 Lacoe Collection, T'nited 

 States National Museum. 



