136 Transactions of the Society^ 



Dakota and Wyoming districts have yielded forty-nine species, 

 and the Maryland localities seven. 



The specimens are often extremely numerous; thus the twenty- 

 nine species from the Black Hills of South Dakota are represented 

 by nearly 1000 more or less complete trunks. In fact, the Cyca- 

 dophyta of the American Mesozoic are as important to the botanist 

 as the gigantic Saurians (with which they are often associated) are 

 to the zoologist. 



Plate VI. fig. 1 represents the first American fossil Cycad 

 ever discovered ; it was found about 1860 in Maryland, between 

 Baltimore and "Washington, by the geologist, Philip Tyson, and well 

 illustrates the external features of the group. A third of a century 

 elapsed before any further discoveries were made, so the present 

 magnificent material has been accumulated within quite a short 

 period. The systematic arrangement of the specimens has been 

 principally the work of Professor Lester Ward, while the morpho- 

 logical investigation has fallen to the share of Dr. Wieland, of 

 Yale University, to whom the discoveries we have now to consider 

 are due. 



It may be mentioned, in passing, that the American palseo- 

 botanists use Buckland's generic name Cycadeoidca for plants which 

 in Europe we should refer to Carruthers' genus Bennettites. Buck- 

 land's genus was founded on trunk-characters, while the diagnosis 

 of Bennettites embraces the fructifications. In referring to Dr. 

 Wieland's work I shall follow him in using the name Cycadeoidea^ 

 but it must be understood that this is synonymous, so far as we 

 can tell, with Bennettites. 



The richness of the American material enables us to form a 

 good general idea of the habit of the family. The trunks were in 

 no case very lofty — there seems to be no good evidence for a height 

 of more than 10 or 12 feet, while the great majority of the stems' 

 were quite short. In some cases the stems are nearly spherical, 

 and several are connected together, evidently as branches of one 

 plant. In comparing these fossils wath recent Cycads, we must, 

 therefore, think of the short-stemmed genera, such as Bovienia or 

 Stangeria, or at the most Macrozamia, rather than of tall plants 

 like Cycas itself, some species of which are said to reach a height 

 of 60 feet. In foliage and the external features of the trunk, 

 there was on the whole the same general resemblance to modern 

 Cycads which has already been noted, and the same striking dif- 



EXPLANATION OF PLATE VIII. 



Fig. 4. Cycadeoidea dacotcnsis. Longitudinal section of flower. The centre is 

 occupied by the long ovuliferous cone, on either side of which are seen 

 parts of the compound stamens, with rows of synangia on their pinnae. 

 To the left, some of the bracts are well shown, x 3 diam. Photo- 

 graph, from Wieland's " American Fossil Cycads." 



