The most characteristic feature of _Calamodendron_ is the occurrence of several rows of radially disposed thick-walled prosenchymatous elements (fig. 84, _b_) on either flank of each wedge-shaped group of xylem. Each principal ray is thus nearly filled up by bands of fibrous cells on the sides of adjacent xylem groups, but the centre of each principal ray is occupied by a narrow band of parenchyma (fig. 84, _c_). The relative breadth of the xylem and prosenchymatous bands has been made use of by Renault as a specific character in _Calamodendron_ stems. Fig. 84 is copied from a drawing recently published by this French author of a new species of _Calamodendron_, _C. intermedium_[635]. In this case the bands of fibrous cells, _b_, are slightly broader, as seen in a transverse section of the stem, than the bands of xylem tracheids, _a_. The narrow band, _c_, consists of four rows of the parenchymatous tissue of a medullary ray. At the inner end of each group of tracheids there is a large carinal canal. The question of the recognition of the pith-casts of stems possessing the structure of any of the three subgenera of _Calamites_ is referred to in a later section of this chapter. _b._ _Leaves_ _Leaves of Calamites and Calamitean foliage-shoots, including an account of_ (α) Calamocladus (Asterophyllites) _and_ (β) Annularia. Our knowledge of the structure and manner of occurrence of Calamite leaves is very incomplete. There are numerous foliage-shoots among the fossils of the Coal-Measures which are no doubt Calamitean, but as they are nearly always found apart from the main branches and stems, it is generally impossible to do more than speak of them as probably the leaf-bearing branches of a Calamite. The familiar fossils known as _Asterophyllites_, and in recent years often referred to the genus _Calamocladus_, are no doubt Calamitean shoots; but they are usually found as isolated fragments, and it is seldom that we are able to refer them to definite forms of _Calamites_. Another common Coal-Measure genus, _Annularia_, is also Calamitean, and at least some of the species are no doubt leafy shoots of _Calamites_. Although it is generally accepted that the fossils referred to as _Asterophyllites_ or _Calamocladus_ are portions of _Calamites_, and not distinct plants, it is convenient, and indeed necessary, to retain such a term as _Calamocladus_ as a means of recording foliage-shoots, which may possess both a botanical and a geological value.