progymnosperms

These were joined by progymnosperms, which rooted up to about a metre deep, during the ensuing Frasnian stage.

Noeggerathiales have been previously linked to horsetails and ferns, but are currently believed to be progymnosperms.

Early characteristics of seed plants were evident in fossil progymnosperms of the late Devonian period around 380 million years ago.

These groups include the Rhyniophyta, Zosterophyllophyta, Trimerophytophyta, and the progymnosperms.

Rothwell's analysis separates the "trimerophytes" and progymnosperms, with only the latter being closely related to seed plants.

In Late Devonian times, another group of progymnosperms gave rise to the first really large trees known as Archaeopteris.

However, they are not a clade (monophyletic group) because the seed plants are also descended from within this group-probably close relatives of the progymnosperms.

They probably evolved from a group of Late Devonian progymnosperms known as the Aneurophytales, which had large, compound frond-like leaves.

By the Late Devonian, forests of large, primitive plants existed: lycophytes, sphenophytes, ferns, and progymnosperms had evolved.

The more familiar leaves, megaphylls, are thought to have separate origins - indeed, they appeared four times independently, in the ferns, horsetails, progymnosperms, and seed plants.

These early seed plants ranged from trees to small, rambling shrubs; like most early progymnosperms, they were woody plants with fern-like foliage.

The progymnosperms are an extinct group of woody, spore-bearing plants that is presumed to have evolved from the trimerophytes, and eventually gave rise to the gymnosperms.

Archaeopteris is a member of a group of free-sporing woody plants called the progymnosperms that are interpreted as distant ancestors of the gymnosperms.

The oldest fossil evidence of seed plants is of Late Devonian age and they appear to have evolved out of an earlier group known as the progymnosperms.

These progymnosperms were the first plants to develop true wood, grown from a bifacial cambium, of which the first appearance is in the mid Devonian Rellimia.

As taller and more complex plants evolved, modifications in the alternation of generations evolved; in the Paleozoic era progymnosperms reproduced by using spores dispersed on the wind.

Several different clades had developed a shrubby or tree-like habit by the Late Givetian, including the cladoxylalean ferns, lepidosigillarioid lycopsids, and aneurophyte and archaeopterid progymnosperms.