220 G. R. Wieland — American Fossil Cycads. 



Prof. L. F. Ward, however, has recorded his opinion that 

 this horizon is Cretaceous.* While these fossil Cycads must 

 eventually prove of much greater value to stratigraphy than 

 isolated leaves, as pointed out by Prof. Marsh, their present 

 interest is mainly of a structural character. 



The living Cycads constitute one of the most ornate and 

 characteristic orders of plants, and, occupying, as they do, a 

 position on the border-land between the higher Cryptogams 

 and lower Phanerogams, their ancestral relationship is of con- 

 siderable interest in itself, though but little progress has yet 

 been made in working out their phylogeny, owing largely to 

 imperfect knowledge of the fossil forms. 



The Male Flower of Gycadeoidea ingens. Ward. 



The male fructification of fossil Cycadean trunks has not 

 hitherto been determined with certainty. An element of doubt 

 surrounds the identity of the separate inflorescences usually 

 held to have been derived from extinct Cycadece, due to the 

 fact that the Mesozoic Cycads were accompanied by a rich, 

 varied, and closely related coniferous vegetation. In the ab- 

 sence of microscopic characters, it becomes a matter of much 

 difficulty to separate with certainty the fructifications of 

 Cycads from those of some Conifers. 



Previous observations on this subject are hence quite limited. 

 Of the supposed fossil Cycadean male fructifications, the pyri- 

 form axis described by Williamson 2 has given rise to the most 

 discussion. While it is not necessary to review the literature 

 on this subject here, it may be mentioned that Seward, 14 after 

 declaring his belief that the Wealden examples of Williamsonia 

 are generically identical with Bennettites, writes as follows : — 

 "As regards the question of male and female inflorescence, I am 

 unable to recognize any sexual differences in the various 

 examples from the Wealden beds, and there does not seem to 

 be any good reason for regarding the so-called male William- 

 sonias among the Jurassic specimens as in any way proved to 

 be of that nature. In comparing Williamsonia with Bennet- 

 tites we have to rely solely on the female inflorescence of the 

 latter plant, and it would seem, so far as our present evidence 

 goes, we have more reason for speaking of Williamsonia as 

 the female inflorescence. As to the nature of the male 

 inflorescence we are still without satisfactory evidence." As 

 will be shown later, the present investigations add a strong 

 degree of probability to this view, if they do not indeed 

 demonstrate its correctness. The reviews of Solms-Laubach, 9 

 and of Schimper 7 who alludes to the male axis of Williamsonia 

 as a Fandanus-like form, may also be consulted. 



* The Cretaceous Rim of the Black Hills.— Journal of Geology, vol. ii, pp. 

 250-266, 1894. 



