Phylum: Tracheophyta
Classification of plant fossils (Kingdom: Plantae) is not as straightforward as classification of animal fossils (Kingdom: Animalia). The biggest difference is the use of the terms division and phylum. Some botanists (people who study plants) use the term Division; others use the term Phylum. Because scientists cannot agree, and to simplify our terminology for 4-H members, we will use the term Phylum, and the related classes as they are found in literature.
To confuse things further, it is common for a single plant to be assigned to several genera; one for the root, one for the leaves, one for the trunk, and possibly another genus for the fruit. This is due to the plant fossil remains being disassociated from each other.
The phylum Tracheophyta is assigned to vascular plants. There are five classes we commonly collect in Kansas.
Class: Lycopsida
Club mosses, which reproduce by spores, comprise this class. It includes the genera Sigillaria, Stigmaria, and Lepidodendron.
Class: Sphenopsida
Horsetails, which also reproduce by spores, are assigned to this class. It includes the genera Calamites, Annularia, Sphenophyllum, Equisetites, and Asterophyllites.
To confuse things further, it is common for a single plant to be assigned to several genera; one for the root, one for the leaves, one for the trunk, and possibly another genus for the fruit. This is due to the plant fossil remains being disassociated from each other.
The phylum Tracheophyta is assigned to vascular plants. There are five classes we commonly collect in Kansas.
Class: Lycopsida
Club mosses, which reproduce by spores, comprise this class. It includes the genera Sigillaria, Stigmaria, and Lepidodendron.
Class: Sphenopsida
Horsetails, which also reproduce by spores, are assigned to this class. It includes the genera Calamites, Annularia, Sphenophyllum, Equisetites, and Asterophyllites.
Class: Filicopsida
These are the true ferns, the third class which reproduces by spores, rather than seeds. The genus Pecopteris is assigned to this class.
These are the true ferns, the third class which reproduces by spores, rather than seeds. The genus Pecopteris is assigned to this class.
Class: Gymnospermopsida
Gymnosperms reproduce by seeds. They differ from the Angiosperms in that their seeds are naked, exposed in cones. There are a number of different orders within this class.
Order: Pteridospermales -- the seed ferns Pennsylvanian and Permian
Genera include Alethopteris, Neuropteris, Mariopteris, Sphenopteris, and Cyclopteris.
Order: Cordaitales Pennsylvanian and Permian
The genus Cordaites is collected at several locations in eastern Kansas.
Order: Voltziales Pennsylvanian and Permian
The genus Walchia is collected in eastern Kansas.
Order: Ginkgoales Triassic to Recent
The genus Ginkgo is the only surviving genus of this order.
Order: Coniferales Triassic to Recent
Pine trees and other conifers are assigned to this order.
Gymnosperms reproduce by seeds. They differ from the Angiosperms in that their seeds are naked, exposed in cones. There are a number of different orders within this class.
Order: Pteridospermales -- the seed ferns Pennsylvanian and Permian
Genera include Alethopteris, Neuropteris, Mariopteris, Sphenopteris, and Cyclopteris.
Order: Cordaitales Pennsylvanian and Permian
The genus Cordaites is collected at several locations in eastern Kansas.
Order: Voltziales Pennsylvanian and Permian
The genus Walchia is collected in eastern Kansas.
Order: Ginkgoales Triassic to Recent
The genus Ginkgo is the only surviving genus of this order.
Order: Coniferales Triassic to Recent
Pine trees and other conifers are assigned to this order.
Class: Angiospermopsida Cretaceous to Recent
Angiosperms are flowering plants, which reproduce by seeds. Their flowers have ovaries containing ovules. These develop into seeds within fruits. This class includes grasses, cattails, clovers, elms, oaks, and maples. The grasses, cattails, and clovers are monocotyledons; the trees are dicotyledons. The genera include Ficus, Sassafras, Aralia, Populus, Laurus, Salix, Persoonia, Cinnamomum, and others.
Angiosperms are flowering plants, which reproduce by seeds. Their flowers have ovaries containing ovules. These develop into seeds within fruits. This class includes grasses, cattails, clovers, elms, oaks, and maples. The grasses, cattails, and clovers are monocotyledons; the trees are dicotyledons. The genera include Ficus, Sassafras, Aralia, Populus, Laurus, Salix, Persoonia, Cinnamomum, and others.
Most of the fossilized wood we collect in Kansas is not found in situ. That is, it is not commonly collected where the tree fell. That makes accurate identification, even to the class level, virtually impossible. When collecting petrified wood from sand and gravel pits, rivers, streams, and similar sites, we assign the wood to the phylum Tracheophyta and do not attempt further identification. There are some sites in Kansas where the wood is found in association with the leaves, and the plant fossils have not been moved since they fell. In these cases, we are able to find further identification in the literature, sometimes including the genus.
The specimens below cannot be identified past the phylum.
The specimens below cannot be identified past the phylum.