This fascinating family is known only from the fossils, and is so remote in its organization from any common living forms that it may perhaps be a little difficult for those who do not know the Cycads to appreciate the position of Bennettites. It would probably be better for one studying fossil plants for the first time to read the chapters on the Cycads, Pteridosperms, and Ferns before this chapter on the present group, which has characters connecting it with that series. Until recently the bulk of the fossils which are found as impressions of stems and foliage of this family were very naturally classed as Cycads. They are extremely common in the Mesozoic rocks (the so-called Age of Cycads), and in the external appearance of both stems and leaves they are practically identical with the Cycads. A few incomplete fructifications of some species have been known in Europe for many years, but it is only recently that they have been fully known. This is owing to Wieland’s[12] work on the American species, which has made known the complete organization of the fructifications from a mass of rich and well-petrified material. In the Lower Cretaceous and Upper Jurassic rocks of America these plants abound, with their microscopic structure well preserved, and their fructifications show an organization of a different nature from that of any past or present Cycad. Probably owing to their external appearance, Wieland describes the plants as “Cycads” in the title of his big book on them; but the generic name he uses, _Cycadeoidea_, seems less known in this country than the equally well-established name of _Bennettites_, which has long been used to denote the European specimens of this family, and which will be used in the following short account of the group. At the present time no family of fossils is exciting more interest. Their completely Cycadean appearance and their unique type of fructification have led many botanists to see in them the forerunners of the Angiosperms, to look on them as the key to that mystery—the origin of the flowering plants. This position will be discussed and the many facts in its favour noted, but we must not forget that the _Bennettitales_ have only recently been realized fully by botanists, and that a new toy is ever particularly charming, a new cure particularly efficacious, and a new theory all-persuasive.