The specimen, of which part of the surface is shown in fig. 174, is in all probability _L. aculeatum_ Sternb. This was described by me in detail in _The Annals of Botany_ (1906) as another example of the co-existence of the _Lepidodendron fuliginosum_ type of anatomy with a true _Lepidodendron_. The locality of the specimen is not known. The leaf-cushions are 1·5 cm. long with tapered upper and lower ends; a ligular cavity may be recognised on some parts of the fossil, also faint indications of leaf-trace scars. The tubercles (fig. 174, A–C, _t_) probably represent leaf-traces which the shrinkage of the superficial tissues has rendered visible in the lower part of their course. The circular scar, _s_ (fig. B), on the partially decorticated surface is apparently a wound. The stele is sufficiently well preserved to justify its reference to _L. fuliginosum_. The irregularly crenulated edge of the primary xylem, _x_ (fig. 175), is succeeded by a broad band of parenchyma (the meristematic zone), _m_, and beyond this are remnants of the secretory zone, _s_. The structure of the leaf-traces corresponds with that of other specimens of the type, but the much steeper course of these vascular strands, _lt_, _lt′_ (fig. 176), is a feature in which this example differs from most of those referred to _L. fuliginosum_. Such evidence as is available would seem to point to the absence of trustworthy criteria enabling us to separate, on anatomical grounds, _Lepidophloios_ and _Lepidodendron_[334]. [Illustration: FIG. 177. _Stigmaria radiculosa_ (Hick). (From sections in the Manchester University Collection.)] _Stigmaria radiculosa_ (Hick).