The spores of the Dinantian lycopsid cone Flemingites scottii from Pettycur, Fife, Scotland

Abstract

Cones belonging to arborescent lycopsids occur abundantly in the Pettycur Limestone facies of the Asbian (late Dinantian, Carboniferous) at Pettycur, Fife. The most abundant cones are heterosporous and have been described by Wiliamson, Scott and others under the name Lepidostrobus veltheimianus Sternberg. Jongmans subsequently named these cones L. scotii Jongmans and the species was later transferred to the cone genus Flemingites. The type specimens (which are in a thin section) are cones which contain both megaspores and microspores. The megaspores can be identified in section as Lagenicula subpilosa (Ibrahim) f. major Dijkstra ex Chaloner and have been figured by numerous authors. The microspores which occur in sporangia at the tip of the cone belong to the genus Lycospora. A new species L. chaloneri is here erected for these spores. Spores have been extracted from new specimens of cones and studied using light and scanning electron microscopy, and their ultrastructure investigated using transmission electron microscopy. Under TEM the exine of Lagenicula consists of a solid basal lamina with an inner exine composed of small globular units which become larger and interlnked in the outer exine. The microspores are small (20 micrometer) subtriangular with a distinctive distal ornament of small (1-2 micrometer) conate-echinate spines. They have a two-layered wall.