JURASSIC FLORA OF DOUGLAS COUNTY, ORF(}. 101 



They aro attached l)y tlie eiitiie l)ase to the sides of the axis of the leaf, 

 nearly oi' (|uile at ;i ii<iht angle. The width is the same from the hase to 

 near the tip, where they are usually slightly uari'owed, so Ihat ihey have 

 elliptic terminations. They are genei'ally not veiy closely placed. They 

 vary somewhat for different leaves in length and widtli, and in the same 

 leaf l)ecome shorter toward the l)ase and probably toward the end. No 

 ends were seen. Taking the leaflets from near the middle pai1 of the leaf 

 as the normal ones for description, the average length may be put at 25 

 mm. and the average width at 3-4 nun. As exti'eme variations we may 

 have in similar parts leaflets 35 mm. long and (i nnn. wide for the maxinuun 

 size and 10 nnn. long and 3 mm. wide for the minimum. The variation is 

 mainly in length. Xathorst in his diagnosis of the species says that the 

 nerves of the leaflets are mostl}' dichotomous at base. In the Oregon 

 specimens they may be dichotomous at or near their bases, but the}' are 

 mostly single, especially in the smaller forms. They are parallel to one 

 another and slender, not Ijeing easily seen without the help of a lens. 

 They do not vary much in strength from their base to their entls, and are 

 10-12 in number. 



PI. XX, Fig. 1, gives a portion of what seems to have lieen the middle 

 part of a leaf, with leaflets of maximum size. The terminations of most 

 of them are not shown. Fig. 2 shows a fragment of a similar part of a 

 leaf carrying narrower leaflets, but of a length equal to that of those given 

 in Fig. 1 . This large form is cjuite conmion at locality Xo. 2 and is mostly 

 missing elsewhere. It is strikingly like P. Jageri Brougn. of the Trias. 

 Fig. 3 is an enlargement of two of the leaflets of Fig. 2. Fig. 4 shows the 

 middle part of a smaller form with leaflets still rather wider than the 

 average. Fig. 5 gives a fragment of a leaf with leaflets that may be taken 

 as average ones. Fig. 6 shows the middle part of another leaf with 

 average-size leaflets. Fig. 7 shows the upper part of one of the leaves 

 with the smallest leaflets. 



The plant is most common at locality Xo. 7, where the average and 

 •smaller forms are found. The larger forms are abundant at locality Xo. 2. 

 to the exclusion of others. It occurs also at localities Xos. 1, 4, and 19. 



