Mesocalamites haueri (STUR) HIRMER , 1927

Mesocalamites haueri (STUR) HIRMER, 1927

Text-fig. 5d View Text-fig

1877 Calamites haueri STUR , p. 195, pl. 2, fig. 7, pl. 5, figs 2, 3.

1927 Mesocalamites haueri (STUR) HIRMER , p. 382.

1969 Calamites haueri STUR ; Crookall, p. 626, pl. 113, fig. 3, pl. 114, figs, 1–3, pl. 115, pl. 116, fig. 1.

1969 Calamites roemeri GÖPP. ; Crookall, p. 622, p. 122, fig. 4.

1969 Calamites approximatiformis STUR ; Crookall, p. 629, pl. 118, fig. 2.

D e s c r i p t i o n. Stems with coarse longitudinal ribs up to 4 mm wide, distally rounded with prominent circular tubercle. Nodes spaced up to 20 mm apart, with internodes sometimes wider than long, in others they may be more than twice as long as wide; at nodes, the ribs may pass straight through or be slightly offset. Occasional isolated oval branch scars sometimes occur immediately above node.

R e m a r k s. This fossil-species represents the coarseribbed mesocalamitid stems found in these floras. They bear a superficial resemblance to Calamites suckowii BRONGN. , which is widespread in the Westphalian macrofloras of Euramerica but the latter has ribs that are more consistently offset at the nodes. Jongmans (1911) queried the significance of this differences, but overlooked the occurrence of occasional branch scars in M. haueri of a type rarely if ever seen in C. suckowii .

The specimens figured by Crookall as Calamites roemeri and Calamites approximatiformis have the coarse ribs with large distal tubercles similar to M. haueri . Crookall differentiated C. roermeri and C. approximatiformis mainly in them having more circular branch scars. However, neither of his specimens of these species show this feature and the justification for distinguishing them taxonomically seems weak.

O c c u r r e n c e s. Only in Upper Limestone Formation, notably below Castlecary Limestone, Bilston Burn, Midlothian.