Archaeopteridium tschermakii (STUR) KIDST., 1923

Archaeopteridium tschermakii (STUR) KIDST., 1923

Text-fig. 10b, c View Text-fig

1875 Archaeopteris tschermakii STUR , p. 57, pl. 12, fig. 1, pl. 16, fig. 1.

1894a Plumatopteris elegans KIDST. , p. 258, pl. 5, fig. 1.

1923 Archaeopteridium tschermakii (STUR) KIDST. , p. 182, pl. 40, fig. 3, pl. 41, figs 1, 2, pl. 43, fig. 6.

1923 Plumatopteris elegans KIDST. ; Kidston, p. 185, pl. 41, figs 3, 4, pl. 43, figs 4, 5.

D e s c r i p t i o n. Bipinnate frond fragments with longitudinally striate rachises. Ultimate pinnae with up to 9 alternately attached pinnules. Pinnules oblong, spathulate to obovate. Distal pinnules with entire margin, and broadly and decurrently attached to rachis; more proximal pinnules tend to become somewhat lobed and basally constricted, but never petiolate. Several radiating veins enter the pinnule at its base; in larger pinnules, an incipient midvein may develop.

R e m a r k s. This is a rare but widespread species in upper Visean and Serpukhovian floras. The types of P. elegans were described by Kidston (1923) in close association with A. tschermakii and were only differentiated by adjacent pinnules being more fused along the rachis; they undoubtedly represent variation within A. tschermakii (see also comments by Rowe 1992: 883).

O c c u r r e n c e s. Several occurrences in the Lower Limestone Formation, and from ironstone bands below the Black Metals Band (Limestone Coal Formation).