Sphenopteridium dissectum (GÖPP.) SCHIMP., 1874

Sphenopteridium dissectum (GÖPP.) SCHIMP., 1874

Text-fig. 7e View Text-fig

1852 Cyclopteris dissecta GÖPP. , p. 161, pl. 14, figs 3, 4.

1874 Sphenopteridium dissectum (GÖPP.) SCHIMP. , p. 488, pl. 107, fig. 12.

1923 Sphenopteridium dissectum (GÖPP.) SCHIMP. ; Kidston, p. 160, pl. 37, figs 1–4.

D e s c r i p t i o n. Bipinnate fragments with clear transverse marks on the rachises. Ultimate pinnae up to 30 mm long, closely-spaced (often touching); pinnae have a pair of oblique, obovate pinnules in the proximal part, and a cuneate terminal pinnule comprising up to 7 segments with rounded apices. Pinnules thick-limbed with a rugous surface. Numerous fine, dichotomous, radiating veins.

R e m a r k s. None of the Scottish specimens figured by Kidston (1923: pl. 37, figs 1–4) shows the diagnostic features of a Sphenopteridium frond. However, specimens of this species from Saalfeld ( Ludwig 1869: pl. 22, fig. 3) and Upper Silesia ( Stur 1875: pl. 5, fig. 8) show the characteristic dichotomy with pinnae attached below the fork (see comments by Kidston 1923). Clusters of Calathiops -like ovulate structures were found associated with these fronds at Swinless Glen and described and figured by Crookall (1976: pl. 171, figs 15, 16) as Lagenostoma smithii KIDST. ex CROOKALL.

O c c u r r e n c e s. Rare in Lower Limestone Formation, mainly from just above the Hurlet Limestine, and one record from the lower Limestone Coal Formation (Garibaldi Ironstone, Dalry).