JURASSIC FLORA OF DOUGLAS COUNTY, OREG. 89 



Phylum SPERM^TOFHYT^.'^ 



Class GYMNOSPEEM.E. 



Order CYCADALES. 



Family CYCADACE^. 



Genus PTILOZAJVIITES Nathorst. 



Ptilozamites Leckenbyi (Bean) Nathorst. 



PI. XVI, Figs. 1, 2. 



1863. Otenis Leclienhyi Bean in Leckenby : Quart. Jour. Geol. See. London, Vol. XX, 



p. 78, pi. X, figs, la, lb. 

 1864? Odoiitopteris f Leckenbyi (Bean) Zign.: Fl. Foss. Form. Oolith., Vol. I, p. 111. 

 1869. Cycadopteris Leckenbyi (Bean) Schimp.: Pal. Veg., Vol. I, p. 487. 

 1880. Ptilozamites Leckenbyi (Bean) Nath. : Ofv. K. Svensk. Vet.-Akad. Forh., Vol. 



XXXVII, No. 5, pp. 65, 8.3. 



Phillips has given a figure of a plant which he calls Odontopteris 

 Leckenbyi (Bean) Zign./ that agrees exactly with a small fragment found 

 at locality No. 19. Although the Oregon specimen is but a small fragment 

 of an ultimate pinna, it has several perfect pinnules that show the nerves 

 very distinctly. The form of the pinnules and the character of the nerves 

 are so entirely characteristic that a single pinnule would suffice to identify 

 the plant. The agreement of the pinnules and nervation with those 

 points in Phillips's figure is exact. The rachis is slender. The pinnules 

 are remote, attached by the entire base to the sides of the rachis and 

 slightly decurrent. They are oblong, falcate, narrowed at the ends by 

 having their posterior margins curve forward toward the ends of the 

 pinna. The nervation is of the Odontopteris type. There is no mid- 

 nerve, but the nerves go off at an oblique angle and curve suddenly and 

 strongly away from the rachis. They are subparallel and branch several 

 times, the center ones more copiously than the outer ones. The last 

 branching is near the tip of the pinnule. 



This species differs from Ctenopteris cycadea Sap., of the Lias, in the 

 more falcate form of the pinnules, and especially in the more copious 

 branching of the nerves. The fact that nearly all the branches again 



"See footnote to Brj'ophytii, p. 53. ''Geology of Yorkshire, 3d ed., p. 218, lign. 41. 



