Plants

	Mineralogy	Geologic Range	Habitat	reproductive body	Other
Chlorophyta*	calcium carbonate, organic	Precambrian - Recent	terrestrial, freshwater, marine	n/a	green algae
Lycophyta*	organic	Devonian - Recent	terrestrial	spores
Sphenophyta*	organic	Devonian - Recent	terrestrial	spores	horestails and friends
Pteriophyta*	organic	Devonian - Recent	terrestrial	spores	true ferns
Pteridospermophyta	organic	Carboniferous - Cretaceous	terrestrial	pollen/seeds	seed "ferns"
Coniferophyta*	organic	Carboniferous - Recent	terrestrial	pollen/seeds	evergreens, pines
Magnoliophyta*	organic	Jurassic(?) - Recent	terrestrial, freshwater, some marine (e.g. mangroves)	pollen/seeds (flowers and fruit)	flowering plants

* Extant Taxa

Ranges of major plant groups

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Division Chlorophyta

This group includes all of the marine, lacustrine, and terrestrial green algae. Algae are very important primary producers in nearly all wet environments. The group contains many forms with non-mineralized skeletons which have a rather poor fossil record. Some forms, such as dascyclad algae (remember the receptaculids?) and other calcareous algae, do secrete a calcium carbonate skeleton. In tropical carbonate environments, calcareous algae contribute vast amounts of sediment to carbonate systems.

Related Websites

• Green Algae (UCMP)

Division Lycophyta

Lycopods have a significant fossil record, and are easily identifiable. The economically important Carboniferous coal deposits are full of lycopod remains, and lycopod remains contributed enormous amounts of organic material to the coal measures. Lycopods have leaves all over their stems, leaving a distinctive pattern of leaf scars all along the trunk and branches. The root system of the large, arborescent lycopods consisted of radiating stigmaria. Lycopods produce spores as part of their reproductive cycle.

Related Websites

• Lycophytes (UCMP)

Division Sphenophyta (Devonian - Recent) While the modern representatives of this division (e.g. horestails) are relatively small in size, those preserved in the fossil record could reach quite large sizes. The group is characterized by ribbed stems with leaves and stems coming off in clusters around nodes along the stem. The morphology is quite distinctive, and easily recognizable in fossil sphenophytes. Sphenophytes produce spores in their reproductive cycle. Related Websites Sphenopsids (UCMP)

Division Pteriophyta (Devonian - Recent) This division includes all true ferns. The "leaves", or megaphylls, of ferns come off of the stem in staggered pairs, and each megaphyll has a central axis. The spores of ferns form in sporangia which are found on both sides of the central axis of the megaphyll. While both spores and macrofossils of ferns are known from the fossil record, "seed" fern remains seem to be more common in Paleozoic and Mesozoic rocks. Ferns, both ancient and modern, do exhibit arborescent habit, and can be large (although not compared to gymnosperms and angiosperms). Related Websites Pteridopsida (UCMP)

Division Pteridospermophyta

(Carboniferous - Cretaceous)

This extinct division includes all of the so-called "seed ferns". While the leaf structure of seed ferns superficially resembles that of true ferns, they are not closely related. While there are many subtle morphological differences between the two groups, the most glaring is that true ferns reproduce using spores, while seed ferns produce pollen and seeds.

Division Coniferophyta (Carboniferous - Recent) The conifers range in size from huge woody trees to small shrubs, and the group includes all forms of "evergreen" trees. The leaves characteristically consist of needles or scales. The wood of conifers is typically dense, and is frequently subject to "petrification" (actually permineralization and/or replacement), and therefore has a relatively high preservation potential. They produce pollen in cones, which is usually broadcast via wind or water to the female reproductive cones. When the female cones mature, they release their load of seeds. Related Websites Conifers (Tree of Life)

Division Magnoliophyta (Cretaceous (Triassic?) - Recent) This group includes all of the angiosperms, or flowering plants. Included are all crop plants (wheat, rice, maize, etc.), all fruit-producing plants (apples, oranges, cantaloupe, etc.), many important fiber-producing plants (cotton, flax, hemp, etc.), and many important woody plants (for construction and pulp). Members of this group have adapted to every imaginable terrestrial environment (e.g. this group includes desert-dwelling cacti), and in some cases members have re-invaded the freshwater realm (lillypads, duck weed, etc.), as well as the ocean shore in salt water (mangroves). Pollen is produced by special structures within the male part of the flower, and delivered to the female portion by some means, usually attached to an animal. Bees and butterflies are major pollen carriers for the modern flora, but many angiosperms have formed co-evolutionary relationships with flies, wasps, beetles, birds, mice, and even lemurs. Related Websites Angiosperms (Tree of Life) Angiosperms (UCMP)

• Plant Taphonomy
• Links for paleobotanists
• Petrified Forest National Monument