84 MESOZOIC FLORAS OF l^NITKD STATKS. 



Zigno has described from tlie Lower Oolite of Italy a fossil with the 

 name Sagenopteris Gappcrtinua" 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-mai'ked character. The lai-gest Oregon leaves have a length of 9 cm. 

 and a width in the widest portion of 35 mm. The leaves vaiy nuich in 

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

 mostly to assume a spatulate shape, widening toward iheii- cuds. 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 very 

 oljtuse at their ends and rovmded. These are rounded off toward their 

 bases elliptically. They 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 show\s consideral)le 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 slendei', 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 

 l)eing short, broad, and l)roadly elliptical, with a rounded base and hardly 

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

 It is only 5 cm. long. This is l)ut slightly inequilateral and may l)e 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 abundant and better material 

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

 fomid in the Oi'oville flora and regarded as Sagenopteris Nilsoniiina'' 

 {S. rhoifolia Presl.). 



PI. XIV, Fig. 5, represents a normal leaf that is strongly inequilatei-al, 

 with a base that is rounded off m an elliptical forai. I'ig. 6 gi\'es the ter- 



"Flor. Foss. Form. Oolitli., Vol. I, pp. 188-190, pi. .\xi, figs. 1-5; pi. xxii, figs. 1, 2. 

 ^Twentieth .\mi. Hep. U. S. Geol. Surv., Pt. II, 1900, p. 352, pi. Ivi, fig. 1 ; pi. Ivii, fig. 2. 



