You’ve likely seen or heard about Archaeopteryx, a very important transitional fossil showing the connection between birds and dinosaurs.  (Isn’t it annoying that ID folks and creationists claim no transitional fossils exist no matter how many are found?)  Archaeopteryx is pretty darn cool – it’s got feathers AND dinosaur teeth and claws.  Archaeopteryx is slightly scarier than the average chicken.

By now you’re thinking I’ve misspelled the title of this post. Archeopteris isn’t a typo – it’s another fossil, and one I think is much cooler than Archaeopteryx, even if its Wikipedia page is quite a bit less developed.  The names are similar because Archaeopteryx has feathers and Archeopteris has leaves that reminded some paleobotanists of feathers.

Archeopteris is one of the oldest known plants with wood.  Wood was a big deal in plant evolution.  Without it, plants can’t get very tall.  While Archeopteris had wood like a conifer, its leaves were similar to both ferns and conifers.

One thing that really sets it apart from woody plants today is that it made spores.*  Today, only the oldest lineages of plants, like ferns and moss, make spores.  All living woody plants are seed plants.

• important clarification from The Phytophactor in the comments: “but seed plants make spores, microspores and megaspores, the former disperse as pollen, an endosporic male, and the latter as part of a seed. Carefully cut open a pine nut to expose an embryonic conifer, the surrounding tissue is an endosporic female that developed from a megaspore. Presumably Archaeopteris dispersed both prior to fertilization, i.e., like Selaginella.”