The cladoxylopsids are an extinct group of

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

s related to

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

s and sphenopsids. They had a central trunk, from the top of which several lateral branches were attached. Fossils of these plants originate in the

Middle Devonian In the geological timescale, the Middle Devonian epoch (from 393.3 ± 1.2 million years ago to 382.7 ± 1.6 million years ago) occurred during the Devonian period, after the end of the Emsian age. The Middle Devonian epoch is subdivided into two ...

Early Carboniferous Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican d ...

periods (around ), mostly just as stems. Cladoxylopsida contains two orders. The order Hyeniales is now included in Pseudosporochnales. Intact fossils of the

cladoxylopsid '' Wattieza'' show it to have been a tree, the earliest identified in the fossil record as of 2007. In 2019, experts from

Cardiff University Cardiff University () is a public research university in Cardiff, Wales. It was established in 1883 as the University College of South Wales and Monmouthshire and became a founding college of the University of Wales in 1893. It was renamed Unive ...

, UK;

Binghamton University The State University of New York at Binghamton (Binghamton University or SUNY Binghamton) is a public university, public research university in Binghamton metropolitan area, Greater Binghamton, New York, United States. It is one of the four uni ...

and the

New York State Museum The New York State Museum is a research-backed institution in Albany, New York, Albany, New York (state), New York, United States. It is located on Madison Avenue, attached to the south side of the Empire State Plaza, facing onto the plaza and to ...

discovered more fossils of Cladoxylopsida and

Archaeopteris ''Archaeopteris'' is an extinct genus of progymnosperm tree with fern-like leaves. A useful List of index fossils, index fossil, this tree is found in Stratum, strata dating from the Upper Devonian to Lower Carboniferous (), the oldest fossils b ...

in a quarry in

Cairo, New York Cairo is a Administrative divisions of New York#Town, town in Greene County, New York, Greene County, New York (state), New York, United States. The population was 6,644 at the 2020 census. It is the third largest town in the county. The town i ...

. A recent (2017) discovery in

Xinjiang Xinjiang,; , SASM/GNC romanization, SASM/GNC: Chinese postal romanization, previously romanized as Sinkiang, officially the Xinjiang Uygur Autonomous Region (XUAR), is an Autonomous regions of China, autonomous region of the China, People' ...

in China of early Late

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

( Frasnian, ca. 374 Ma) silicified fossil cladoxylopsid tree trunks (diameter up to c.70 cm) with preserved cellular anatomy showed an internal arrangement with many xylem bundles in the outer part and none in the interior; each bundle was surrounded by its own

cambium A cambium (: cambiums or cambia), in plants, is a tissue layer that provides partially undifferentiated cells for plant growth. It is found in the area between xylem and phloem. A cambium can also be defined as a cellular plant tissue from whic ...

layer, by which the tree's trunk widened.

References

External links

Links with images:
UC Museum of Paleontology
*https://sites.google.com/site/paleoplant/classification/cladoxylopsid Devonian plants Middle Devonian first appearances Mississippian extinctions Plant classes {{carboniferous-plant-stub