Stenokoleales †

Diversity

Brabantophyton runcariense

• Momont et al. 2016

• Middle Givetian to earliest Frasnian (late Middle to earliest Upper Devonian) of Ronquières (Belgium)

• The specimens of Brabantophyton show many similarities with the stenokolealean genus Crossia virginiana (Beck and Stein), but the vascular supply of lateral organs of the latter consists of a more symmetrical and distinctively simpler pair of traces. 

• Brabantophyton represents the first report of the Stenokoleales in southeastern Laurussia. The characteristics of the Brabantophyton protostele compare better with the anatomy of the radiatopses, and, within the latter, particularly with basal seed plants.

Stems 

• Protostele dissected into three primary ribs, each of them dividing into two secondary ribs

• The protostele shows a central protoxylem strand and numerous strands distributed along the midplanes of the ribs

• The vascular supply to lateral organ is composed of two pairs of traces, produced at the same time by the two ribs issued from a single primary rib of the protostele

• Within each pair, the shape and the size of the traces are unequal: one is T-shaped and the other is oval to reniform

  • The T-shaped traces of each pair face each other

• The inner cortex of the lateral organs is parenchymatous and the outer cortex is sparganum-like.

Crossia virginiana

• Beck & Stein 1993

• Late Eifelian (Middle Devonian)

? Gothanophyton zimmermannii † 

• Remy and Hass 1986

• late Emsian (Early Devonian) of West Germany

• Winged stem with vascular bundles from the central strand

• Possibly aligned with Stenokoleales; possibly aligned with Aneurophytales; Possibly ancestral euphyllophyte to the progymnosperms