THE JURASSIC FLORA OF CAPE USBURNE, ALASKA. 49 



arc least uniteil. Toward the ends of the ultimate pinnae and m the ternnnal portions of the 

 compound ends they are more and more united and pass into lobes and teeth, the size being 

 at the same tmie diminished. 



The nervation is described bj^ Fontaine as follows: 



The midnerve goes off very obliquely and at aliout two-thirds the distance to the end of the pinnule splits up 

 into branches, after the fashion of Cladophlebis, so that the plant is a well-marked type of that genus and in the absence 

 of fructification must be placed in it. The lateral nerves, in proportion to the size of the pinnules, are quite slender. 

 They are immersed in the leaf substance and are not conspicuous. They go off very ol^liquely and are forked one or 

 more times. The lowest are the most copiously branched. The forking is notably low down on the nerve, so that 

 the branches are unusually long. On the lower side of the base of the pinnules one or more lateral nerves go off from 

 the main rachis. In the more separated pitnudes the lower lateral nerves curve away from the midnerve, but in the 

 lobed and dentate forms the interior basal ones often curve inward toward it. 



On takmsi everything mto account it seems ]irobab]e that this fern should receive a new 

 name, but it is so robust and abunihmt a form that it probajjly had a wide distribution hi 

 Arctic lands, not bemg conhned to the vicinity of Cape Lisburne, and rather than give it a 

 name which might possibly prove to be a synonym of some form known from less oomjilete 

 material, I am permitting it to remam under the name given by Fontame. It is very much 

 to be doubted, however, that this fern is identical with the Neuropteris huttoni of Dunker. 



?Cladophlebis alata Fontaine. 

 Plate V, figures 3, 4; Plate VI, figure 4. 



"iCladophlebis alata Fontaine, in Ward, U. S. Geol. Survey Mon. 48, p. 158. PI. XXXIX. figs. 9-11: PI. XL, 190.5. 

 Onychiopsis psilotoides (Stokes and \\ebb) Ward, idem, p. 1.55, PI. XXXIX, figs. 3-6. 

 Pecopteris r/enticulata Heer. Lesrjuereux. II. S. Xat. Mus. Proc, vol. 11, p. 32, 1888. 



It is with much hesitation that this s])ecies is permitted (o remaui under tlie designalioit 

 given it by Fontauie in his review of the flora of Cape Lisburne, especiaUy in view of the fact 

 that BeiTV ' has merged the origmal C. alata with C. browniana (Dunker) Seward, a common 

 form in the Patuxent and .^Vrundel formations of Maryland and Virgiuiu. That it is identical 

 with the Potomac forms is extremely doubtful, but that it is the same as the numerous speci- 

 mens from Cape Lisburne that were so designated by Fontauie there can of course be no ques- 

 tion. At first it was thought that this form represented the sterile foliage of Coniopteris hure- 

 jensis, and tliis supposition may ultimately be verified. For instance, the jiortion of the sterile 

 puma shown hi Plate \', figure 4, is ccrtaudy strikingly similar to the upper jihuia on the right- 

 hand side of the figure* of C. burejensis shown m Plate V. They are of about the same size, 

 have the linear puinules set at the same strict angle, and are cut nearly to the same degree. 



It is not to be denied that the sterile portions of the specimens here called CladopMebis 

 aUita have a rather strikmg resemblance to Onychiopsis psilotoides (or mantelli, as it is more 

 frequently called). Thus, the very large lower pmna showai in Plate V, figure 3, is similar 

 ui general appearance to the figure given bj' Seward - of a specmien. of 0. mantelli from the 

 English Wealden. Both these specimens show well the strict habit of the plants, and both 

 lack the fuier details of the outlmcs of the ultimate divisions. In the iUaskan specimen the 

 phmules are somewhat larger, but otherwise the difference is apparently not great. It was, 

 of course, this general resemblance which induced Fontauie '' to identify certaui specunens 

 in the earlier collections as Onychiopsis psilotoides, yet it is impossible to distuiguish these 

 from a large niunber here referred to (Jladopidehis alata. For mstance, the puma showii in 

 Plate V, figure 3, is not to be separated from figure 5 of Fontame's plate above cited. 



On the whole it seems best, pending the finduig of additional material, to leave this form 

 under the name given it by Fontame, with the frank confession that such disposition is recog- 

 nized as neither adequate nor final. 



' Berry, E. W., Maryland Geol. Survey, Lower Cretac»ous, p, 24:j, 1!I12. 



» Seward, A. C., Fos.sil plants of the Wealden, pt. 1, 1'l. II, fig. 1, 1894. 



' Fontaine, W. \L, U. S. Geol. Survey Mon. 48, p. 155, PI. XXXIX, figs. »-6, 1905. 



