=Stigmaria.= _Stigmaria ficoides_ is the name given to cylindrical casts met with in Palaeozoic rocks, from the Devonian[553] to the Permian[554], characterised by a smooth or irregularly wrinkled surface bearing spirally disposed circular scars bounded by a raised rim and containing a small central pit. It is not uncommon to find evidence of a partial collapse of the substance of the plant as seen in fig. 204; this is doubtless the expression of a shrinkage of the middle cortical region, which was composed of a delicate and lacunar system of cells. There can be no reasonable doubt that Stigmaria grew in water or in swampy ground. Specimens are occasionally met with in which the cast terminates in a bluntly rounded apex; such are, perhaps, young branches which have not grown far from the base of the aerial stem from which they arose (cf. fig. 207, B, C). Other examples occur, such as Goeppert[555] figured and Gresley[556] has more recently described, which are twisted and distorted as though obstacles had been encountered in the ground in which they grew. [Illustration: FIG. 204. _Stigmaria ficoides_ Brongn. M.S. (See Vol. I. p. 73.)] [Illustration: FIG. 205. _Stigmaria ficoides._ From a specimen in the York Museum, from Bishop Auckland. _a_, base of rootlet showing vascular bundle scar. M.S.] The circular scars mark the bases of long single and occasionally forked appendages (rootlets) which spread on all sides into the surrounding medium (figs. 205, 208). The occurrence of rootlets radiating through the shale or sandstone affords proof that the Stigmarias are often preserved in their position of growth. This was recognised by Steinhauer[557] and Logan[558], and has been more recently emphasised by Potonié[559] as an argument in favour of the view that the beds containing such specimens are old surface-soils. _Stigmaria_ usually shows regular dichotomous branching, the arms spreading horizontally or slightly downwards and always arising from four main branches in the form of a cross (fig. 207). The most remarkable specimens found in England are described by Williamson[560] in his monograph of _Stigmaria_. One of two large casts found near Bradford in Yorkshire, and now in the Manchester Museum, shows four large primary arms radiating from the base of an erect stump 4 feet in diameter. Each arm divides a short distance from its base into two, and the smaller branches extend almost horizontally for several feet[561].