FLORA OF THE SHASTA FORMATION. 237 



Sagenopteeis nervosa Fontaine n. sp. 

 PI. LXV, Figs. 41-4.5. 



A number of fragments of detached pinnules of a fern with anastomos- 

 ing nerves which seems to be a new species of Sagentopteris were found at 

 several locahties. None of the specimens show the pinnules entire, and 

 the nervation is not very distinct, but by taking imprints of different 

 pinnules, and different portions of these, a pretty good description can be 

 made out. This, however, owing to the imperfection of the material, can 

 not be regarded as certainly accurate. 



Pinnules very large, probably grouped in a digitate manner at the 

 summit of a principal stipe. The central pinnule is elliptical and sym- 

 metrical in form, narrowing gradually to the base. It is at least 8 cm. long 

 and 3 cm. wide. The size of the other, or lateral pinnules, could not be 

 made out, but they appear to be somewhat smaller, inequilateral, and 

 unsymmetrical in form. The nerves are unusually strong and they are 

 rather remote. The midnerve is rounded and very strong in the middle 

 pinnule toward its base, and it ends in a short stipe. Toward the middle 

 of the pinnule it splits up into nerves. The nerves in the lower portion of 

 the pinnule go off very obliquely from the midnerve, and curve gradually 

 away from it to the margin of the pinnule, forking repeatedly. In the 

 upper portion the branches into which the midnerve splits up by their 

 repeated forking fill the lamina of the pinnule. The anastomosis is most 

 commonly formed by a branch of a nerve joining an adjacent nerve, but 

 sometimes by two adjacent branches coalescing. 



PL LXV, Fig. 41, represents the basal portion of a middle pinnule. 

 Fig. 42 the upper portion of a large pinnule, probably a middle one, and 

 Fig. 43 the tip of a lateral pinnule. Fig. 44 gives an enlargement of a 

 portion of a pinnule to represent the character of the nerves. Fig. 45 

 represents the specimen from Riddles, Oreg. 



This plant occurs at localities Nos. 16 and 18, in the California dis- 

 trict, and in the Horsetown beds near Riddles, Oreg. At least a smaU 

 fragment was found there, showing the characteristic nervation. The 

 plant seems to have been rather rare at all the localities. 



