The oldest known body fossils of land plants are Silurian in age.  Fossil root traces of land plants are known back in the Ordovician.  The Devonian was the key time interval during which land plants flourished and Earth experienced its first “greening” of the land.  The earliest land plants were small and simple and probably remained close to bodies of water.  By the Late Devonian, land plants had evolved large, tree-sized bodies and the first-ever forests appeared.



Baragwanathia from the Lower Devonian of Victoria, southeastern Australia.  This is the oldest known lycopod plant and one of the oldest known land plant body fossils.  Lycopods are an important and well known component of the Paleozoic land plant fossil record.  Baragwanathia occurs in the Upper Silurian to Middle Devonian of Australia and Canada, principally from impressions and carbonized compressions, but some specimens are permineralized.  Baragwanathia was a decent-sized plant, with upright axes (stems) up to 7 cm wide, but did not get too big - it was a herbaceous plant that probably stood less than ~1 m high.  Numerous elongated leaves (microphylls) attached to the axis in a helical pattern.  Individual leaves reached up to 4 cm long.

Classification: Plantae, Lycophyta, Drepanophycales

(FMNH PP48927, Field Museum of Natural History, Chicago, Illinois, USA)




Archaeosigillaria (a.k.a. Clwydia) from the Devonian at Gilboa, southeastern New York State, USA.

This distinctive fossil plant is also a lycopod, the best-known plant group in the Paleozoic fossil record.  This plant was a relatively small, herbaceous lycopod that had simple, bifurcate branching.  The leaves (microphylls) were small and generally needle-like (see the spine-like structures alongside the stems in the above specimens), and were attached to the stem (axis) in a helical pattern.

Classification: Plantae, Lycophyta, Protolepidodendrales

(FMNH P21749, Field Museum of Natural History, Chicago, Illinois, USA)



Colpodexylon deatsii Banks, 1944 from the Oneonta Formation (lower Upper Devonian) of Sullivan County, southeastern New York State, USA (FMNH PP 33689, Field Museum of Natural History, Chicago, Illinois, USA).  Colpodexylon is another lycopod plant, like Archaeosigillaria (above).  Each dimple on the stem is a leaf attachment star.  The leaves were trifurcate (three-branched) and very thin & elongated, like modern pine needles.  Leaves were attached to the stem in a subtle helical/spiral arrangement.

Classification: Plantae, Lycophyta, Protolepidodendrales



Aneurophyton from the Devonian at Gilboa, southeastern New York State, USA.  These are branches from an extinct group of vascular plants, the aneurophytalean progymnosperms.  Progymnosperms have characteristics of seed plants (they have lots of gymnosperm-like wood - secondary xylem) and characteristics of ferns (fern-like reproductive structures that produce spores).  Aneurophyton is a progymnosperm that has non-flattened branches that emerge from the main axis of the plant in a helical or decussate fashion.  The photosynthetic structures in Aneurophyton are not true leaves - they are usually referred to as “pre-leaves”.  This plant produced spores having one morphology but a range of sizes (70 to 150 μ in the same plant).

Aneurophyton has been reported from the Devonian of Europe, Russia, and America.

Classification: Plantae, Progymnospermophyta, Aneurophytales

(FMNH P21741, Field Museum of Natural History, Chicago, Illinois, USA)




Archaeopteris cf. Archaeopteris halliana from the Devonian of Quebec, southeastern Canada (left) & Archaeopteris from the Devonian of Pennsylvania, USA (right).

These are branches with leaves from another progymnosperm plant.  In the 1960s, the leaf/frond genus Archaeopteris was recognized to be part of the same plant as the wood genus CallixylonArchaeopteris had 3 to 4 feet diameter trunks (axes) and formed shrubby to tree-sized plants, possibly similar to modern conifers.  The leaves (they are recognized as true leaves in this form) are flattened and range in shape from spatulate to fan-shaped to dissected.  Species of Archaeopteris have been reported from the Devonian of North America, Eurasia, and Australia.

Classification: Plantae, Progymnospermophyta, Archaeopteridales

(FMNH PP16302 (above left) & FMNH UP 2054 (above right), Field Museum of Natural History, Chicago, Illinois, USA)



Chaleuria cirrosa Andrews et al., 1974 from the upper Lower Devonian of New Brunswick, southeastern Canada (FMNH PP 33636, Field Museum of Natural History, Chicago, Illinois, USA).    Chaleuria is the oldest known plant that has heterospory - its sporangia produced spores of two discrete size ranges.  Heterospory became a widespread reproductive feature in land plants by the Late Devonian.  Chaleuria was initially interpreted as a progymnosperm (see above), but it has since been considered to have uncertain affinities (Plantae incertae sedis).



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