XLI] . CZEKANOWSKIA 67 



genus. The leaves are generally slightly narrower than the 

 unbranched needles of G. Murrayana, but the habit of the dwarf- 

 shoots is the same. The leaves often show fine striations; in 

 most specimens there is no indication of clearly marked veins 

 though two or three vascular strands are sometimes visible. 

 Heer on very slender evidence refers to this species some seeds 

 and a 'male flower.' 



It is not always easy to distinguish between imperfect examples 

 of C. rigida and Baiera Lindleyana : the leaves of the latter type 

 are petiolate and the segments diverge at a wider angle. Two 

 leaves with spreading bifurcate segments figured by Fontaine^ 

 from Lower Cretaceous rocks in the Black Hills as Czekanowskia 

 nervosa Heer afford no indication that they were borne in clusters 

 on dwarf-shoots but resemble the petiolate leaves of Baiera 

 Lindleyana. Berry^ points out a similarity between Fontaine's 

 fossils and Baiera foliosa Font. Heer's type-specimens of C. 

 nervosa from the Wealden of PortugaP are more like Czekanoivskia 

 leaves. The leaves described from Siberia as C. setacea Heer*, 

 though narrower than some forms of C. rigida, are probably not 

 specifically distinct. 



Czekanowskia rigida is characteristic of Jurassic strata, and 

 occurs in Europe, including Greenland, also in Siberia, China, and 

 Japan. 



Czekanowskia dichotoma Heer and C. capillaris Newberry. 



The branched leaves described under these names ^ from 

 Cretaceous rocks in Greenland and North America are in most 

 cases not sufficiently complete to be assigned with certainty to 

 the genus Czekanowskia; the examples figured by HoUick and 

 Jeffrey^ from Middle Cretaceous beds as C. capillaris occur in 

 closely packed groups, but no specimens have been discovered 

 showing any scale-covered supporting axis. While admitting the 

 probability that these species and C. nervosa'^ from Wealden strata 



1 Fontaine in Ward (99) B. p. 685, PI. olxix. figs. 1, 2. 



2 Berry (11) p. 374. » jieer (81) PI. xvii. 

 « Heer (77) ii. p. 68; (78) ii. p. 26; (82) A. p. 18. 



5 Heer (82) A. p. 8. Newberry and Hollick (95) p. 61. 

 ' HoEick and Jeffrey (09), B. p. 63, PI. VI. figs. 1—3. 

 ' Heer (81) PI. xvn. 



5—2 



