84 MESOZOIC FLORAS OF UNITED STATES. 



Zigno has described from the Lower Oohte of Italy a fossil with the 

 name Sagenopteris Gceppertiana " that exactly resembles a plant occurring 

 rather abundantly at some of the Oregon Jurassic localities. He gives a 

 number of figures which show that the plant varies a good deal. Most of 

 these variations can be seen in the Oregon specimens. The plant has a 

 well-marked character. The largest Oregon leaves have a length of 9 cm. 

 and a width in the widest portion of 35 mm. The leaves vary much in 

 size and in other points. They are all decidedly inequilateral and tend 

 mostly to assume a spatulate shape, widening toward their ends. Occa- 

 sionally a leaf shows a narrowing at the tip, so that it is subacute. These 

 seem to be the central leaves of a group. But most of them are ver^^ 

 obtuse at their ends and rounded. These are rounded off toward their 

 bases elliptically. The}' are apparently the lateral leaves of a group. 

 Some of the obtuse leaves are narrowed gradually to their base, giving 

 the base a prolonged wedge form. None were seen attached. The mid- 

 nerve shows considerable variation. In the leaves with prolonged wedge- 

 shaped bases it is carried two-thirds of the length of the leaf. In those 

 with the most marked inequilateral forms and elliptic bases it is not 

 so prolonged, going, at most, one-third of the length of the leaf; in 

 some it is hardly at all developed. The secondary nerves are not dis- 

 tinct. They are very closely placed and slender, anastomosing so as to 

 form long meshes. The branches in anastomosing meet at very acute 

 angles. One form that seems to belong to this species is abnormal in 

 being short, broad, and broadly elliptical, with a rounded base and hardly 

 any development of midrib. Another is alDnormal in being very small. 

 It is only 5 cm. long. This is but slightly inequilateral and may be a form 

 of Sagenopteris paucifolia. This is proportionally not smaller than the 

 fossil given by Zigno, pi. xxi, fig. 2, but it is narrower and proportionally 

 longer than Zigno' s plant. 



From an inspection of the more alDundant and better material 

 obtained at the Oregon localities, I am convinced that this plant is the one 

 found in the Oroville flora and regarded as Sagenopteris Nilsoniana^ 

 (S. rhoifolia Presl.). 



PL XIV, Fig. 5, represents a normal leaf that is strongly inequilateral, 

 with a base that is rounded off in an elliptical form. Fig. 6 gives the ter- 



"Flor. Foss. Form. Oolith., Vol. I, pp. 188-190, pi. xxi, figs. 1-5: pi. xxii, figs. 1, 2. 

 ^Twentieth Ann. Rep. U. S. Geol. Surv., Pt. II, 1900, p. 352, pi. Iri, fig. 1; pi. Ira, fig. 2. 



