The cladoxylopsids are a group of plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s known only as fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s that are thought to be ancestors of fern

Fern

A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

s and horsetail

Horsetail

Equisetum is the only living genus in the Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.Equisetum is a "living fossil", as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and...

s.

They had a central trunk, from the top of which several lateral branches were attached. Fossils of these plants originate in the Middle Devonian to Early Carboniferous periods (around ), mostly just as stems.

Cladoxylopsida contains two orders. The order Hyeniales is now included in Pseudosporochnales

Pseudosporochnales

Pseudosporochnales is an order of the extinct cladoxylopsids. It contains the Hyeniales....

.

Intact fossils of the Middle Devonian cladoxylopsid Wattieza

Wattieza

Wattieza was a genus of prehistoric trees that existed in the mid-Devonian that belong to the cladoxylopsids, close relatives of the modern ferns and horsetails...

show it to have been a tree, the earliest identified in the fossil record as of 2007.