Calymmotheca stangeri STUR , 1877

Calymmotheca stangeri STUR, 1877

Text-fig. 8b, c View Text-fig

1877 Calymmotheca stangeri STUR , p. 257, pls 8–9.

1924 Calymmatotheca stangeri STUR ; Kidston, p. 465, pl. 105, figs 1–7, pl. 106, figs 1–9, pl. 107, figs 1–6.

D e s c r i p t i o n. Spinose stems up to 30 mm wide bearing helically-arranged fronds; both stems and rachises with anastomosed surface patterning. Petiole / primary rachis of fronds dichotomous producing divergent, tri-to quadripinnate, lanceolate to ovate pinna-branches, with ultimate pinnae borne both below and above the dichotomy. Ultimate pinnae linear-lanceolate to lanceolate depending on position in frond, bearing alternately to oppositely arranged pinnules. Pinnules thick-limbed, quadrate-ovate to triangular-ovate, basally constricted, with entire margin or shallowly lobed. Veins thin, dichotomous, with several veins entering each pinnule lobe. Cupulate ovules borne on rachises lacking sterile pinnule.

R e m a r k s. This species is the type of the fossil-genus Calymmotheca . It is very similar to Calymmotheca dubuissonis (BRONGN.) STUR as occurs abundantly in the Serpukhovian of Maine-et-Loire, France ( Bureau 1914, Strullu-Derrien et al. 2021) but the latter has pinnules that are more oblique to the rachis, are more divided and have more acute lobes. It is not widespread in the Scottish Serpukhovian floras, although at least it was reported as very abundant in Braidbar Quarry and Robroyston Pit that allowed Kidston (1924) to prepare a detailed description.

O c c u r r e n c e s. Below Orchard Limestone, Upper Limestone Formation, from New Braidbar Quarry and Robroyston Colliery.