Plant

Classification

Evolutionary Ordering of Plant Groups

A cladogram of the evolutionary relationships of land plants (embryophytes) and possible origination during geologic time. The phylogenetic relationships are based upon studies that incorporate fossil taxa, which may give different results than purely molecular cladistics. The thick-labeled bars indicate evidence for macrofossils of each group during geologic time.

Below you will find the evolutionary or phylogenetic groupings of land plant groups, based upon current research. Click on a group to learn about their characteristics, time range, and evolutionary significance.

= Extinct; * Diverts to Plant Diversity website

Classification

Nematophytes: strange, fungal-algal organisms from the Paleozoic

Archaeplastida *: clade including red algae, green algae, and land plants

Red algae *: The phylum Rhodophyta

Viridiplantae *: a clade including the green algae and land plants

Chlorophytes *: some green algae

Streptophytes: a clade including land plants, the charophytes, and zygnematophytes

Charophytes: a group green algae closely-related to land plants

Embryophytes: another name for "land plants"

Bryophytes *: non-vascular plants

Hornworts *: non-vascular thalloid plants with horn-like sporophytes

Setaphytes: non-vascular plants with a seta stalk

Liverworts *: non-vascular plants with thalloid and leafy forms

Mosses *: non-vascular leafy plants

Polysporangiophytes: plants with sporophytes that branch

Eophytes †: branching, non-vascular plants

Horneophytes †: branching, non-vascular plants

Aglaophyton : branching, non-vascular plants

Tracheophytes: another name for the clade of vascular plants

Rhyniales †: ancestral vascular plants

Eutracheophytes: clade of "true" vascular plants

Cooksonioids †: oldest known vascular plants

Lycophytes: clade with clubmosses and zosterophylls

Zosterophylls †: leafless relatives of clubmosses

Sawdoniales †: derived zosterophylls

?Barinophytes †: heterosporous zosterophylls?

Lycopsida: the clubmosses or lycopods

Drepanophycales †: ancestral, extinct clubmosses

Protolepidodendrales †: extinct clubmosses with forked leaves

Lycopodiales *: ground pines, princess pines, etc.

Selaginellales *: spikemosses

Isoetales *: quillworts

Pleuromeiales †: Mesozoic group of cormose clubmosses

Lepidodendrales †: tree-sized clubmosses, called scale trees

Euphyllophytes: a clade of true-leaved plants

Trimerophytes †: ancestral euphyllophytes that probably form a grade

Eophyllophyton †: early plant with megaphyllous leaves

Monilophytes: a clade representing modern and ancient ferns, as well as horsetails

Cladoxylopsida †: ancient tree-sized fern-like plants

Iridopteridales †: intermediates between trimerophytes and horsetails

Pseudosporochnales †: a group of the earliest known tree-sized plants

Eospermatopteris †: earliest known tree-like plant on Earth

Equisetophytes: horsetails, scouring rushes, and their ancient relatives

Pseudoborniales †: the most ancient group of equisetophytes

Sphenophyllales †: horsetail-like plants with ambiguous connections

Equisetales: Modern horsetails, including ancient calamites

Stauropteridales †: Ancient ferns with obscure leaf-stem transition

Rhacophytales †: Ferns dominant in Late Devonian understory

Zygopteridales †: Late Paleozoic ferns with quadriserate fronds

Psilotales *: leafless and rootless extant ferns

Ophioglossales *: obscure ferns related to Psilotales

Marattiales: ancient tree ferns with eusporangia

True ferns *: modern ferns mostly with leptosporangia

Pertica †: taxon intermediate between early forms and woody plants

Lignophytes (woody plants)

Progymnosperms †: spore-bearing, woody plants

? Eophyllophyton †: Early Devonian plant with true leaves that are flattened stems

Aneurophytales †: vine-like, leafless progymnosperms

Stenokoleales †: Possible progymnosperm or seed plant

Archeopteridales †: earliest true trees with woody growth

Protopityales †: obscure progymnosperms known mostly from anatomy

Noeggerathians †: heterosporous progymnosperms dominant during Permian

Spermatophytes (seed plants)

Basal seed plants †: Late Devonian seed plants, known as seed ferns

Lyginopteridales †: early arborescent seed ferns

Medullosales †: early arborescent seed ferns with large seeds

Buteoxylonales †: poorly understood pteridosperm groups

Callistophytales †: Best known Paleozoic seed plants

Calamopityales †: Mississippian pteridosperm with indistinct stem and leaf anatomy

Cycadales: palm-like, cone-bearing plants that are still extant on Earth

Dirhopalostachtaceae †:

Gigantopteridales †: complex seed ferns of the Permian

Nystroemiaceae †: Permian seed plants with derived stems and leaves

Hermanophytes †: enigmatic gymnosperms from the Late Mesozoic

Iraniales †: obscure gymnosperms from the Late Triassic

Peltaspermales †: gymnosperms with umbrella-like reproductive structures

Corystospermales †: successful fern-like gymnosperm during the Triassic

Czekanowskiales †: Mesozoic seed plant that may be related to ginkgoes

Ginkgophyta: Ginkgo; maidenhair trees

Vladimariales : Mesozoic seed plants

Vojnovskyales †: gymnosperm with umbrella-like cone and fan-shaped leaves

Coniferophytes: conifer clade

Cordaitales †: Paleozoic gymnosperms with cones and strap-like leaves

Voltziales †: ancestral conifers

Conifers: extinct and extant cone-bearing, (mostly) evergreen gymnosperms

Gnetophytes *: gymnosperms with angiosperm-like leaves and cones

?Anthophyte clade: hypothesized clade of plant groups related to angiosperms

Glossopteridales †: Permian gymnosperms with tongue-like leaves

Petriellales †: Triassic plants found in Antarctic understory

Pentoxylon †: Mesozoic gymnosperms with complex leaves and pulpy cones

Bennettitales †: cycad-like gymnosperms with flower-like cones

Doyleales †: obscure Cretaceous gymnosperm with carpel-like ovulate organs

Caytoniales †: small trees with possible affinities with angiosperms

Angiosperms: flowering, fruiting plants