Dr Kidston[496] is of opinion that certain species of _Sigillaria_ bore cones sessile on large vegetative shoots characterised by two opposite rows of cup-like depressions like those in the Ulodendron form of _Lepidodendron Veltheimianum_ (fig. 157). He has described the Ulodendron condition of two species, _Sigillaria discophora_ (König) and _S. Taylori_ (Carr.); the cup-like depressions may have a diameter of several centimetres and are distinguished from those of _Bothrodendron_ by the almost central position of the umbilicus. The specimens which he figures as _S. discophora_ are identified by him with the stem figured by König as _Lepidodendron discophorum_ and by Lindley and Hutton[497] as _Ulodendron minus_. We have already dealt with the nature of Ulodendron shoots, expressing the opinion that in spite of the often quoted specimen described by D’Arcy Thompson[498], in which a supposed cone occurs in one of the cups, there is no satisfactory case of any undoubted cone having been found attached to the large Ulodendron scars. It is more probable that the Ulodendron depressions represent the scars of branches, either elongated axes, or possibly in some cases deciduous tuberous shoots which served as organs of vegetative reproduction. A specimen figured by Kidston as _Sigillaria Taylori_ from the Calciferous sandstone of Scotland[499] bears a row of slightly projecting “appendicular organs” attached to a Ulodendron axis; but these furnish no proof of their strobiloid nature. The main question is, are these Ulodendron shoots correctly identified by Kidston as Sigillarian? The surface of the specimens shows crowded rhomboidal scars surrounded in some cases by a very narrow border or cushion; the general appearance is, as Kidston maintains, like that of _Sigillaria Brardi_ in which the leaf-scars are contiguous (e.g. fig. 203, upper part). None of the leaf-scars exhibit the three characteristic features, the leaf-trace and parichnos scars, but only one small scar appears on each leaf-base area. In a more recent paper Kidston figures a small piece of a stem from Kilmarnock, which he identifies as _Sigillaria discophora_, showing the three characteristic scars on the leaf-base area. There is no doubt as to the Sigillarian nature of this specimen, but it is not clear if the piece figured is part of a Ulodendron shoot[500].