578 STUDIES IN FOSSIL BOTANY 



are included by their investigators in Buckland's 

 genus Cycadeoidea (synonymous with Bennettites of Car- 

 ruthers 1 ), but a new genus, Cycadella, has been founded 

 by Lester Ward for a number of dwarf stems, dis- 

 tinguished by their abundant ramental covering, 

 which often envelopes the trunk ; twenty species have 

 been referred to this genus, which is characteristic of 

 somewhat older beds than those in which Cycadeoidea 

 is prevalent. 



Anatomically, the American stems so far investigated' 

 agree wonderfully closely, often down to the most 

 minute detail, with the European species of Bennettites. 

 It is, however, quite probable that when the investi- 

 gation of the vast material has proceeded further, 

 more variety may be found. As regards the form and 

 structure of the leaves of the Bennettiteae, practically 

 all our information comes from Dr. Wieland, who in 

 various specimens has succeeded in finding the young 

 leaves still folded in the bud and preserved in great 

 perfection. His observations were chiefly made on 

 Cycadeoidea ingens, a species in which he estimates the 

 length of the mature leaf at about 10 feet, and on 

 Cycadella ramentosa, a much smaller plant, so that both 

 the later and the earlier types are represented. It is 

 sufficient, without going into details, to say that Dr. 

 Wieland's investigations show that in form, prefoliation, 

 venation, and anatomical structure these leaves show a 



1 The name Cycadeoidea is employed by some European writers for trunks 

 of the Bennettitean type without fructifications, as in the case of Professor 

 Seward's Cycadeoidea ingens. In discussing the American species, I follow 

 the usage of the palasobotanists of that continent, employing the names 

 Cycadeoidea and Cycadella throughout. It is desirable, however, that an 

 agreement as to the nomenclature should be arrived at. 



