The form of some of the vascular bands in the section of _Psaronius infarctus_ shown in fig. 296, A, illustrates the occasional anastomosing of one dictyostele with another: the different degrees of looping of other bands represent stages in the giving off of leaf-traces which eventually pass out as =V=-shaped meristeles. Beyond the leaf-traces and sclerenchymatous bands the section consists of transverse sections of adventitious roots. The surface-features of _Psaronius infarctus_ are probably represented, as Zeiller points out, by the cast described by Lesquereux as _Caulopteris peltigera_ (fig. 298, A). [Illustration: FIG. 297. _Pecopteris Sterzeli_: a, pinnule. (After Renault and Zeiller. ¹⁄₁₁ nat. size.)] The Psaronius shown in fig. 297 is one of the few examples illustrating the connexion between fronds and stem. The leaf (_Pecopteris Sterzeli_ Zeill. and Ren.[1071] is quadripinnate and is described as reaching a length of at least 3 metres; the ultimate segments are entire or lobed. The stem is characterised by elliptical scars, 6–8 cm. x 3·5–4 cm., with leaf-traces like those in _Caulopteris peltigera_. The fronds of _Pecopteris Pluckeneti_, a Pteridosperm, bear a very close resemblance to those of _P. Sterzeli_, which are as yet known only in a sterile state. • • • • • _Psaronius brasiliensis_ Unger, a species founded by Unger on a piece of silicified stem acquired by Martius in Brazil and now in the Rio Museum, is a good example of a tetrastichous species. Solms-Laubach[1072] has recently told the history of this type, which is represented by sections, cut from the Rio stem, in several European collections. A well-preserved section in the British Museum is figured by Arber[1073] in his catalogue of the Glossopteris flora and by other authors. Scott gives a concise description of the species in his _Studies in Fossil Botany_[1074]. The roots of _P. brasiliensis_ are stated by Pelourde[1075] to have a lacunar cortex. _Psaronius musaeformis_ Corda[1076]. Fig. 296, D. This species from the Lower Permian of Chemnitz and the Coal-Measures of Bohemia affords an example of the distichous type in which the leaves are borne in two rows. The vascular bands, as seen in a section of the dictyosteles, occur in regular parallel series. The stelar region is separated from the cylinder of encasing roots by a sclerenchymatous sheath, broken at intervals where roots pass out from the vascular region.