JURASSIC FLORA OF DOUGLAS COUNTY, OREG. 125 



leaf in which one side is entire, affording an idea of the width of the leaf. 

 The summit of this is not preserved. 



This plant is much the most common Ginkgo at locality No. 2, 

 where it is abundant. It is also found at local'ties Nos. 4, 7, and 19. 



Ginkgo lepida Heer. 

 PI. XXXII, Figs. 3-8. 



1876. Ginkgo lepida Heer: Fl. Foss. Arct., Vol. IV, Pt. II (Jura-Fl. Ostsibiriens) , 



p. 62, p. vii, fig. 7; pi. xii. 

 1885. Salisburia (Ginlcgo) lepida (Heer) Dn.: Trans. Roy. Soc. Canada, Sect. IV, 



Vol. Ill, p. 8, pi. ii, fig. 2. 



The lepida type of Ginkgo, as given by Heer, is represented in the 

 Oregon flora by a considerable number of specimens. The leaf substance 

 is thick and leather-like. The primarj^ segments are cut down to the 

 base of the leaves, where they are reduced almost to petioles. The 

 secondary segments are long and narrowly elliptical to linear in form, 

 widest near the middle and tapering toward their lower and upper por- 

 tions. This form sometimes tends to pass into the sibirica type by 

 intermediate shapes that are rather common. The lepida type departs 

 further than any other from that of G. digitata. 



PI. XXXII, Fig. 3, gives a nearly entire leaf and one of the largest 

 found. It shows the long narrow segments well. This is shown enlarged 

 in Fig. 4. Fig. 5 shows a primary segment with several ultimate ones, 

 the basal part not being preserved. Fig. 6 denotes a primary segment 

 with the base not preserved, having shorter and proportionally broader 

 ultimate segments than is common. Fig. 7 shows this much enlarged. 

 Fig. 8 gives a portion of a primary segment with three ultimate ones of 

 the smallest size. Owing to the deep incisions of the leaf and its spreading 

 habit, it is rare to find entire leaves of this type. 



This plant is most common at locality No. 19, where it is rather 



abundant. It is also common at locality No. 7. It occurs more rarely 



at locality No. 4. 



Ginkgo sibirica Heer. 



PI. XXXIII. 



1876. Ginkgo sibirica Heer: Fl. Foss. Arct., Vol. IV, Pt. II (Jura-Fl. Ostsibiriens) 

 pp. 61, 116, pi. vii, fig. 6; pi. ix, fig. .5b; pi. xi (excl. fig. 3b); pi. xx, figs. 3b, 

 6c; pi. xxii, fig. 3. 



1885. Salisburia (Ginkgo) sibirica (Heer) Dn.: Ti-ans. Roy. Soc. Canada, Sect. IV, 

 Vol. Ill, p. 8, pi. ii, fig. 1. 



