Sgs STUDIES IN FOSSIL BOTANY 



specimens appear to be known, but the structure has 

 now been interpreted with considerable probability, in 

 the light of that of the hermaphrodite flowers of 

 Cycadeoidea. The middle of the fruit is occupied by a 

 stout pyriform axis, which no doubt represents the 

 central ovuliferous receptacle, while traces of the sur- 

 rounding stamens have also been detected. Williamson 

 described some forms of fructification as male and others 

 as female, but they, in all probability, represent merely 

 different states of preservation of the same bisexual 

 flowers. Details will be found in Wieland's American 

 Fossil Cycads} 



Professor Seward, from the study of an English 

 specimen now at Paris, as well as from other evidence, 

 proved conclusively that the Williamsonia fructifications 

 and the Zamia-\ik& leaves were borne on the same stem. 2 

 He regarded the plant as closely allied to Bennettites? 

 and this view has proved to be fully justified, though the 

 degree of relationship can only be determined when speci- 

 mens of Williamsonia are discovered with microscopic 

 structure preserved. On present evidence, it appears 

 most probable that Williamsonia (of which several 

 species, from various parts of the world, extending 

 to North America and India, are known) belonged 

 to the Bennettitales, differing from Bennettites chiefly 

 in the long peduncles on which the fructifications were 

 borne, and in the taller and more slender stem. 



1 See especially his Plate xlvi. with the description of figures. 



2 Seward, "On the Leaves of Bennettites" Proc. Cambridge Phil. Soc. 

 vol. ix. p. 273, 1897. The critical specimen, showing both leaves and 

 floral peduncles in connection with the stem, has been refigured by 

 Wieland in his paper on Historic Fossil Cycads, above cited. 



3 See his Catalogue of Mcsozoic Plants : Fossil Plants of the Wealden, 

 Pari ii. 1895, anf l Jurassic Flora, Part i. 1900. 



