Callistophytes †

Ecology & Form

• Slender stems indicating vine or shrub

• "Patchy, often dense occurrence within wetland landscapes" (Taylor et al. 2009)

• This plant may have grown in fire-prone areas, allowing these plants to rapidly colonize in light gaps

Stem

• Form genus Callistophyton †

• Eustele with cambium and manoxylic wood

• Axillary branching, unlike other pteridosperms

• Spherical secretory structures found in cortex

Leaves

• Large fronds; up to 30 cm in length (Dicksoniites †)

• There is a proximal dichotomy of the rachis; pinnately compound

• Pinnules are tongue-shaped, and can closely resemble pinnules of Lyginopteridales fronds such as Mariopteris

Roots

• Numerous adventitious roots born at many nodes

Reproduction

• Probably wind-pollinated

Seeds / ovules (e.g. Callospermarion †)

• No cupule

• Platyspermic (flattened seeds)

• Born abaxial on leaf

• Characteristic secretory structures found in ovule

• Integument fused only to the nucellus

• Lagensotome projection present at chazal end, which breaks down to form the pollen chamber.

Pollen-bearing (e.g. Idanothekion †, Callandrium †)

• Fused pollen-bearing structures (synangia) attached abaxially to pinnules

• Small, radially symmetrical

• Each pollen-sac with longitudinal dehiscence

• Pollen similar to conifers: monolete, bisaccate pollen (Vesicaspora)