200 MKSOZOIC FLORAS OF UNITED STATES. 



Leaves of cycadeiia ramentosa Ward. — A closcr examination of the middle one of 

 the three .so<;nients figured by Professor \\'ard in the first paper on the 

 Status of the Mesozoic floras of the United States" possibly representing 

 the main portion of a typical specimen of this species, resulted in the 

 discovery of the two fronds shown in transverse section in PL LXII, 

 Fig. 2, and PI. LXIII, Fig. 1. 



As is represented in the figures, looth of these fronds are very small 

 and are entirely surroimded by remarkal:)ly preserved ramentum. Both 

 these leaves, as will be seen on examining Professor Ward's figure, 

 show'ing very neatly the middle (not terminal) position of the portion 

 of the trunk which bears them, are abnormal in being borne laterally, 

 and not as members of a series forming a crowai of leaves. They grew 

 out, therefore, from between old leaf bases, probably after the crowai 

 of the plant had suffered some injury. As this phenomenon has been 

 observed in some other cases not yet described, I regard it as possible 

 that these plants may have been subject, among other mishaps, to 

 cropping by contemporaneous animals (dinosaurs?). However, this 

 abnormal position does not affect the orientation of these leaves. They 

 are normal in all other respects. Their prefoliation agrees with that of 

 Cycadeoidea ingens, as descri))ed by me. As in that species, they are 

 once pinnate, the petiole being distal and the pinnules'" folded back face 

 to face in tw^o ranks. But in structure there are certain points of differ- 

 ence. In Cycadeoidea ingens the hypodermal sclerenchyma beneath the 

 upper surface of the leaf is continuous with the bundle sheath. In the 

 present specimen there is no such connection, although the bimdle sheath 

 of sclerenchyma is strongly marked, as in the living cycad Ccrnioznmia 

 fuscoviridis [rz C. Mexicana Brongn.]. The prefoliation and arrangement 

 of parts in the present fossil form bear an exceedingly close resemblance 

 to this living form, the closest I know. But, on the other hand, 

 Ceratozamia terrestris, with a strong development of hypodermal ribs of 

 sclerenchyma on both the xylem and phloem side of the pinnule bundles 

 is rather more like Cordaites ("?) anguloso-striatus Gr. Eury., as figured by 



aTwentieth Ann. Rep. U. S. Geol. Surv., Ft. II, 1900, pi. cxxxviii, fig. 2. 



I> These leaves are once pinnate, but since wc liavc bipinnuto cycad leaves (Bowcnia), 1 sliall use the term 

 pinnule rather than pinna. This is the usage in some of our most recent and best pubhcations on ferns, and the 

 terminology of both must obviously be homological. Moreover, this is the more convenient usage, since in the 

 case of many fossil forms the order of the lamina; is not always readily determinable. 



