Voltziales †

Conifer-like gymnosperms

The Voltziales are an extinct group of conifer-like gymnosperms that appear in the Pennsylvanian and disappear during the Cretaceous extinction. There are generally two types of Voltziales: walchian and voltzian. The former had needle-like leaves and branches growing parallel to the ground; the latter had scale-like leaves and more upright branches. It is possible that the Voltziales were intermediate between the true conifers and the cordaites.

Ecology & Form

Two types of Voltiales: walchian and voltzian types

Walchian type

Plagiotropic branching (branches grow parallel to the ground)
Needle-like leaves
Dwarf shoots with radially-arranged scales
Pollen monosaccate

Voltzian type

Orthotropic branching (branches grow upright; perpendicular to ground)
Leaves are broad, dwarf shoots bearing flattened and partially fused scales
Pollen bisaccate
Fused female reproduction organs
Reproduction involves a pollen tube

Classification

└Lignophytes

└Voltziales †

Early conifers; possible intermediate between cordaites and conifers

Geologic Range

Pennsylvanian - Late Cretaceous

Reproduction

Mostly monoecious
Differentiated megasporangiate (♀) and microsporangiate (♂)
Ovuliferous scales
- Highly-condensed, fertile shoot
- Ovuliferous scales clustered into fertile area or cone

Diversity

Families

Bartheliaceae
Buriadiaceae
Emporiaceae
Ferugliocladaceae
Krassiloviaceae
Majonicaceae
Thucydiaceae
Ullmanniaceae
Utrechtiaceae

Select taxa

Aethophyllum stipulare †

Grauvogel-Stamm, 1978; Rothwell, Grauvogel-Stamm, & Mapes, 2000
Middle Triassic of France (~247 Ma)
A "herbaceous" conifer, which had scant amounts of wood
- All living conifers (and gymnosperms for that matter) have robust woody growth
The main trunk grew up to 2 meters in height, which exhibited upright branches with determinate growth
Cones formed at the tips of upper branches
- Female cones are located at the tips of the uppermost branches
- Male cones are located at the tips of the lower shoots.
- Some fertile specimens are as small as 30 cm in height

Above: Aethophyllum stipulare

Pityocladus †

Vegetative branches

Pityophyllum †

Vegetative branches

Schizolepis †

Bilobate cone scales from the Late Triassic to Early Cretaceous of Europe & northern Asia

S. daohugouensis

- Zhang et al., 2011

S. liasokeuperianus

- Braun, 1847

Tobleria bicuspis †

Jongmans & Gothan 1925, 1935
Early Permian (Asselian) from Sumatra
Cylindrical female cones with deeply split cone scales of a possible early Voltzian cone
Seed scales and bract scales are helically- and loosely-arranged on the cone axis (Harris, 1979)

Above: Reconstruction of Tobleria bicuspis (Van Wessen 2019)

Additional Resources

Tobleria Scale Complex growing (2013)

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