The examples of supposed _Equisetites_ sheaths referred to below may serve to illustrate the kind of evidence on which this genus has been recorded from Upper Palaeozoic rocks. I have retained the name _Equisetites_ in the description of the species, but it would probably be better to speak of such specimens as ‘Calamitean leaf-sheaths’ rather than to describe them as definite species of _Equisetites_. We have not as yet any thoroughly satisfactory evidence that the _Equisetites_ of Triassic and post-Triassic times existed in the vegetation of earlier periods. In Grand’Eury’s _Flore du Gard_[501] a fossil strobilus is figured under the name _Calamostachys tenuissima_ Grand’Eury, which consists of a slender axis bearing series of sporophylls and sporangia apparently resembling those of an _Equisetum_. There are no sterile appendages or bracts alternating with the sporophylls; and the absence of the former suggests a comparison with _Equisetites_ rather than _Calamites_. Grand’Eury refers to the fossil as “parfois à peine perceptible,” and a recent examination of the specimen leads me to thoroughly endorse this description. It was impossible to recognise the features represented in Grand’Eury’s drawing. Setting aside this fossil, there are other strobili recorded by Renault[502] and referred by him to the genus _Bornia_ (_Archaeocalamites_), which also exhibit the Equisetum-like character; the axis bears sporophylls only and no sterile bracts. It would appear then that in the Palaeozoic period the Equisetaceous strobilus, as we know it in _Equisetum_, was represented in some of the members of the Equisetales. [Illustration: FIG. 57. A. _Equisetites Hemingwayi_ Kidst. From a specimen in the British Museum. ⅔ nat. size. B. Diaphragm and sheath of an Equisetaceous plant, from the Coal-Measures. ⅔ nat. size. From a specimen in the British Museum.] 1. _Equisetites Hemingwayi_ Kidst. Fig. 57, _A_.