JURASSIC FLORA OF DOUGLAS COUNTY, OREG. 65 



a compound pinna. PI. VIII, Fig. 13, shows one of the pinnae enlarged, 

 and Fig. 14 gives a portion magnified two diameters to show the nerves. 

 PI. VIII, Fig. 15, shows a small fragment of a penultimate pinna, with 

 ultimate pinnae to which are attached fertile pinnules, which present their 

 upper surface uppermost; hence the sori are disguised. As is often the 

 case, these fertile pinnules differ somewhat from sterile ones that come 

 from similar parts of the compound pinna. They are wider in proportion 

 to length and more obtuse. PI. IX, Fig. 1, represents a larger specimen, 

 having sterile pinnules, from a position lower down on the compound 

 pinna than that shown in PL VIII, Fig. 12. They are undulate or dentate. 

 PI. IX, Fig. 2, shows an enlarged pinna. PL IX, Fig. 3, represents a frag- 

 ment from a still lower position, carrying portions of ultimate pinilse and 

 sterile, serrately toothed pinnules. PL IX, Figs. 4 and 5, show magnified 

 pinnules of this. PL IX, Fig. 6, gives terminal portions of ultimate pinnae 

 that apparently correspond with the parts represented in Fig. 3, but these 

 are narrowed by distortion from pressure, the margins being pressed into 

 the rock. If we suppose the parts represented in Figs. 3 and 6 to be com- 

 bined, we may get some idea of the expanse of this elegant fern. PL IX, 

 Fig. 7, gives a small fragment comparable to the portion shown in Fig. 3, 

 but from a lower position on the compound pinna, where the pinnules, by 

 deeper incision, begin to pass into ultimate pinnae. PL IX, Fig. 8, shows 

 one of these pinnules enlarged. PL X, Fig. 1, depicts a specimen of con- 

 siderable size, it being a portion of a penultimate pinna to which are 

 attached a considerable number of ultimate pinnae, carrying crenately 

 toothed fertile pinnules. Unfortunately most of these pinnules are con- 

 siderably distorted, being narrowed by having their margins pressed down 

 into the rock. PL X, Fig. 2, represents the terminal parts of several ulti- 

 mate pinnae with fertile pinnules corresponding in position to the fragment 

 represented in Fig. 1, but in this case they are not distorted. From these 

 the true form of those given in Fig. 1 may be determined. PL X, Fig. 3, 

 shows a single pinnule of this specimen enlarged to show the sori. PL X, 

 Fig. 4, shows a fine specimen. It is a fragment of a penultimate pinna 

 with ultimate pinnae, carrying fertile pinnules of the largest size. They 

 are more deeply incised than the pinnules shown in Fig. 1, and apparently 

 come from lower down on the compound pinna, where the pinnules tend to 

 pass into ultimate pinnae. These fertile pinnules apparently correspond 



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