64 CONIFERAE. 



Oolite of Siberia, and according to Saporta 1 in the Coralline Oolite of 

 France. Better-known species of the genus are Baiera Miinsteriana, Heer, 

 from the Rhaetic beds of Bayreuth, and B. paucipartita, Nath., from the 

 same formation at Schonen. The Chalk also has produced remains of 

 Baiera, which may to some extent be accepted. The leaves of Baiera, 

 which are repeatedly and dichotomously inciso-partite, are distinguished 

 from those of Ginkgo by the shortness of the leaf-stalk and by the narrow 

 ribbon- like form of the greatly elongated leaf-lobes, in which according to 

 Heer there is no further bifurcation of the nerves. In the specimen of 

 B. paucipartita, Nath., figured in Schenk 2 , the leaves which are only slightly 

 divided are seen to be collected together, as in Ginkgo, at the summit of a 

 branchlet. Later investigations leave little room for doubt that Salisburieae 

 are to be found as early as in the Permian formation, and Saporta 3 main- 

 tains that we have the genus Ginkgo itself in his Salisburia primigenia from 

 the Permian deposits of Russia. The habit is not against this conclusion, 

 but I will not venture to decide. The species Baiera digitata, Heer, 

 peculiar to the Kupferschiefer of Europe, was formerly regarded by 

 most writers as an Alga 4 (Fucoides Zonarites) ; it is found usually 

 in somewhat doubtful fragments, seldom in a perfect state, and appears 

 always to have had leaves with only few incisions ; in the American Baiera 

 virginica, Font, et White 5 , the leaf-division was more copious. These 

 authors c also describe a type of leaf from the same formation in Pennsyl- 

 vania as Saportaea salisburioides, Font, et White, in every respect like that 

 of Ginkgo, and with a nervation which is even essentially the same as in our 

 own recent species. The genus Rhipidopsis, Schmalh. also may according 

 to Schmalhausen's 7 description be very near to Ginkgo ; the leaves with 

 their deep flabelliform incisions show similar nervation and symmetrical 

 configuration, the broadly wedge-shaped sections being very large in the 

 middle of the leaf and diminishing very rapidly toward the side, so that 

 they appear at last quite diminutive and rudimentary. 



It was stated above that the leaves of Ginkgo and Baiera of the Lower 

 Oolite of Eastern Asia are associated with fragments of branches, remains 

 of seeds, and male flowers. The branches and seeds are considered by 

 Heer 8 to belong to Ginkgo digitata and also to Baiera Czekanowskiana 9 ; 

 some male flowers and the stalk of a female inflorescence are assigned by 

 him to Ginkgo Huttoni, other male blossoms to G. sibirica. The flowers 

 are really like those of our own plants, but they are perhaps stouter, and 

 have longer filaments standing out stiffly from the axis and bearing at their 

 apex two or three spreading pollen-sacs. Heer's 10 remarks on this point 



1 de Saporta (4). a Zittel (1), p. 262. 8 de Saporta (2), p. 145. * Brongniart (1), t. i, f. 9. 

 8 Fontaine and White (1). Fontaine and White (1), p. 102 ; t. 38. 7 Schmalhausen (1). 



8 Heer (5), vol. 4 i, t. 10. Heer (5), vol. 411, t. 10. w Heer (1), p. 3. 



