70 MESOZOIC FLORAS OF UNITED STATES. 



less than usual of the Cladophebis character. The lateral nerves are 

 strong and very distinct. They are given off at an angle of about 45°, 

 and fork near their insertion. The branches diverge strongly, then become 

 parallel and turn outward to meet the margin under a large angle. One 

 of the branches may fork again, but they are mostly single. Some of the 

 pinnules appear denticulate near their tips, but this may be due to lacera- 

 tion and imperfect preservation. The larger pinnules are about 24 mm. 

 long and 6 mm. wide. 



This fine fern seems identical with the Pecopteris insignis of Lindley 

 and Hutton." The larger pinnules are exactly like the form given by 

 Phillips for this species.'' Seward, in his paper on the Jurassic Plants in 

 the Manchester Museum, identifies this and a number of other species 

 with CladojMebis denticulata (Brongn.) Nath., and on pi. iv he gives a 

 figure of C. denticulata that agrees well with the Oregon plant. The pin- 

 nules of this plant reseml^le so much those of the fine Danceopsis Storrsii, 

 described farther on, that I am inclined to think that they are the sterile 

 forms of that fossil. 



Lindley and Hutton described from the Yorkshire Oolite a fertile 

 fern under the name Pecopteris undans," giving a fructification like that 

 of Danceopsis Storrsii. Seward, in the paper above quoted, p. 19, states 

 that Nathorst had suggested that Pecopteris undans may be the fertile 

 pinna of Cladophlebis denticulata, and further that an examination of sev- 

 eral examples of Pecopteris undayis enabled him to confirm Nathorst's 

 opinion. The fructification, as given bj^ Lindley and Hutton in the figure 

 of P. undans, is strikingly like that of Danceopsis Storrsii and would make 

 the plant a Danseopsis. Seward gives no reason for connecting Clado- 

 phlebis denticulata with this plant. There is no connection between 

 Danceopsis Storrsii and the Oregon form referred to Cladophlebis denticu- 

 lata, hence the latter nmst remain in the genus Cladophlebis. It is, 

 however, significant to find that in both these cases the idea is suggested 

 that the fructification of this Cladophlebis is that of Danseopsis. It 

 should be stated that Seward does not in his remarks indicate the resem- 

 blance of the fructification of Pecopteris undans to that of Danseopsis. 



aFoss. Fl. Gt. Brit., Vol. II, p. 69, pi. cvi. 



!> Phillips, Geology of Yorkshire, 3d ed., p. 206, lign. 17. 



cFoss. Fl. Gt. Brit., Vol. II, pp. 103-104, pi. cxx. 



