.HKASSIC FL01{.\ OF DOUdLAS COrNTY. OHKd. 99 



Tho ])l:uil isv(M-\- ;il)Uii(laiit nt localilx" No. 7. aiul is lioro only iiifoi-ioi' 

 in (luantity to I'li rojtliiiUuni rnjnuihalcHsc. (Sec ]). Id'-'.) ll i>^ voiy 

 aluuidaiil at hicalily No. 4 and is coniinoii al localilx' No. 2. It occurs 

 at localities Xos. S, 12, and H). 



PTEHoriivi.LrM <'o\ rua I M Schciik. 



I>l. XIX, Ki^'s. 7 11. 



18S3. rhriijilnillinii i-oiitiiiiiiDii Schciik: Plhinliclic N'cr.stcincnini^'cii aiis Kiclit- 

 liolVn's Cliina, \'ul. I\'. |). --'(i-'. |)l. liii. li.L'. •>. 



The fossil from tlie Jurassic of China, described hy Schenk i\i> Ftcro- 

 phylluni contignum, seems to be the same as a ])lant that is not rare at some 

 of the Ore.son localities. Schenk seems to have had only one specimen 

 and could not determine its full ch.aracKM-. 'V\\v Oregon specimens ai'e 

 fragments mostly of the middle portions of leaves. The midril) is very 

 strong and rigid in proportion to the size of the leaflets. The leaflets are 

 quite thin in texture. They are lineai- in form, of the same width from 

 base to apex; not falcate, but straight. They are very obtuse at their 

 ends and symmetrically rounded off there. They stand at right angles to 

 the rachis. Their form is much like that of the leaflets of /■•. (rqualc, but. 

 they are mostly narrower. They vary a good deal in size, being in some 

 cases almost as small as the smallest of the leaflets of P. NnUwrsti. The 

 average leaflet is about 2 cm. long and a little more than 2 mm. wide. 

 The smallest forms are somewhat less than 10 mm. long and 2 nmi. wide. 

 These are rare. Schenk shows the leaflets as simply touching one another, 

 but in many of the Oregon forms they not only touch but seem to be 

 united, so as to show l)etween two adjacent leaflets what looks like a strong 

 nerve or cord. This may be simply a line of the rock matter scjueezed 

 l)etween the adjacent leaflets. The distinguishing character of the plant 

 is the constant close approximation of the leaflets. The nerves are slender, 

 and to be seen require the help of a lens. They are al)Out 5 in number, 

 simple, and ])ai'all(>l to one another and to the margins of the leaflets. 



PI. XL\, Mg. 7, gives a portion of the middle part of a leaf carrying 

 leaflets of the largest size, and Fig. 8 shows a poi'tion of this enlarged. 

 Fig. 9 shows a similar part of a leaf witli leaflets of the narrowest kind, and 

 Fig. 10 a portion of the same enlargetl. iMg. 1 1 represents a poorly pre- 

 served portion of a leaf with the narrowest leaflets. 



The plant is most common at locality No. 7, where it is abundant. 

 It is also found at localities Nos. 4 and 19. 



