Biosphere Community
Plant Pages
Diversity of Plants: Major Groups
Plants eat sunlight. Along with algae and cyanobacteria in Earth's waters and on land, plants are the essential basis for all animal life, for plants (and these other photosynthesizers) create food energy using sunlight, water, and carbon dioxide. This process of photosynthesis was Earthlife's greatest invention, for it is the foundation on which virtually all other life rests.
Most plants nowadays are flowering plants (angiosperms), which include most trees, shrubs and herbs, grasses and flowers. Angiosperms are the most recently evolved kind of plant, and dominate terrestrial Earth. Other common groups of plants are conifers, ferns, and mosses.
Millions of years ago, enormous swamp-forests of tree-ferns and cycads were buried and gradually became the coal, oil and natural gas our civilization lives on today. We are living today on fossil sunlight energy captured by plants and stored by Earth a very long time ago.
The Tree of Life grows an incredible diversity of beings. About 350,000 species of plants are estimated to currently exist, including conifers, flowering plants, mosses & liverworts, and ferns & fern allies. Just under 300,000 plant species have been scientifically described, the vast majority being flowering plants. Once flowering plants (angiosperms) developed on Earth, there was an explosion of species, slow in our time-sense, very quickly in evolutionary time.
Contemporary land plants are all multicellular eucaryotes. Most algae are unicellular, and are not presented here. For algae, go here. Almost all land plants feed themselves using photosynthesis; a few are parasitic on other plants, and at least one species is parasitic on a fungus. The cell walls of land plants are made of cellulose.Virtually all land plants have specialized organs, called leaves and leaflets, that carry chloroplasts. Chloroplasts are where photosynthesis takes place. The plant groups shown below are just the most important groups. They appear in the order of their appearance on Earth.
Mosses, Liverworts & Hornworts
(Bryophytes)
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Bryophytes are the earliest multicellular plant pioneers. They first colonized land at the beginning of the Paleozoic Era, about 450 million years ago. Unlike most living plants, bryophytes have no interior vessels to transport water and nutrients. As a result, Bryophytes are small, soft, and most must be near moisture. All bryophytes can reproduce vegetatively, as well as sexually.
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Dicranum moss of the North Woods |
detail of moss stems and simple leaves |
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two mosses, showing differences in size |
moss sporangia, elevated to catch wind |
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liverwort eking out a living in a quartz crevice |
flat thallus liverwort of temperate climates |
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liverworts and mosses cohabit near a stream |
Liverwort Marchantia sporangia |
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Young sporophyte generation of hornwort springs up from the basal gametophyte generation that they live upon. Photo credit Christine Cargill
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a hornwort showing both the long-lived gametophyte generation and the sporophyte generation which gave them the name
"horn-plant" Photo credit David Weber
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Pterodophytes: 20,000 species
Ferns, Ground Pines, and Horsetails |
Ferns and their relatives are vascular plants; they have vessels inside their stems to transport water from roots to fronds, and nutrients from fronds to roots. They can reproduce both sexually, with spores, and vegetatively, from runners.
Pterodophytes emerged on Earth around 359 million years ago.
The three groups shown are ferns, ground pines or club mosses, and horsetails.
Ferns
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maidenhair fern growing on rock face |
ostrich fern fiddleheads unrolling |
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cinnamon fern frond unrolling |
Japanese painted fern |
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cinnamon fern fiddleheads emerging from soil |
epiphyte leathery polypody growing on Sitka spruce, showing red sori, each with hundreds of spores |
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mini-fern green spleenwort just emerging |
cinnamon fern spores |
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Ostrich fern fronds |
sensitive ferns splashed with light |
Ground Pines (Club Mosses)
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round branch ground pine, a club moss |
ground cedar, a club moss |
Horsetails, Equisetum
These early plants contain silica and have been used to
scour pots since the first pots were built.
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the radial symmetry of horsetail leaf whorls |
typical horsetail frond |
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horsetail spore-bearing strobilus |
horsetail silica-bearing "scouring rush" |
Seed Plants: Conifers
630 species
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Conifers appeared on Earth some 300 million years ago. While there are a comparatively small number of species, conifers are ecologically central to life in the northern hemisphere; they dominate the great circumpolar forests of the taiga.
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California coastal pine, probably Pinus contorta contorta |
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Bristlecone Pine @ 12,000', thousands of years old
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bristley cone on Bristlecone Pine |
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cone of Ponderosa Pine, seeds dispersed |
Ponderosa Pine seeds winged to spin away |
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conifer meadow, Mt. Shasta |
bough of incense cedar |
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tender new growth on an ancient California Redwood tree |
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Utah Juniper |
cones of Western Hemlock |
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Tamarack in autumn, a deciduous conifer |
tops of mountan Sequoia |
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male cones of red pine, soon to release pollen |
enormous base of mountain sequoia |
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new growth on Silver Fir @ 7,000' |
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gigantic trunk of California Coast Redwood |
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developing cone of Red Pine |
young female cones of Red Pine |
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Flowering Plants (Angiosperms)
Water Lilies, Monocots and Dicots
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Water Lilies, a basal group of 80 species
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yellow waterlily, also called spatterdock |
white water lily |
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Nympheas by Claude Monet, ca 1915 |
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A lilypad growing toward light |
a mature spatterdock flower |
Monocotyledons
50,000 to 60,000 species; important foods
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arrowhead, aquatic Sagittaria |
perfoliate bellwort, a woodland wildflower |
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Virginia bluebells, woodland wildflower |
chiondoxa, cultivated spring bulb |
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turkscap lily, a fresh meadow wildflower |
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lily, coastal California |
giant Solomon's seal, woodland wildflower |
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rose pogonia, a wild bog orchid,
like all orchids, a monocot |
crocus, cultivated spring bulb |
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daylily, cultivated monocot |
iris yellow flag, the original fleur de lis |
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chives, like entire onion family, monocot |
Trillium, woodland wildflower |
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wild iris on marshland |
wild lily of valley, emerging from soil |
Monocots: Grasses
9,000-10,000 species; crucial crops
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Seedhead of Big Bluestem of the tallgrass prairie |
flowers of Big Bluestem of the tallgrass prairie |
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seed spike of timothy grass |
typical panicle arrangement of seeds |
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flowers of Little Bluestem, native prairie grass |
Indian rice grass seedheads, New Mexico desert |
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seedhead of rattlesnake grass, California |
detail of anthers of big bluestem |
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inflorescence of a marsh grass |
inflorescence of redtop grass |
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stems of wheat, oncea wild grass |
diversity of Maize seedheads, once a wild grass |
Dicots, most numerous plant group
175,000-200,000 species |
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Birdsfoot Trefoil, naturalized immigrant |
Brown-eyed Susan, native wildflower |
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Sky Blue Asters in August, native wildflower |
Prairie Clover, native wildflower |
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Teddybear Cholla cactus, Joshua Tree, CA |
Red Barrel cactus, Joshua Tree, CA |
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wild Bottle Gentian, petals must be forced apart by bumblebees for pollination |
wild Columbine in bud and flower |
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wildflower butterfly weed |
daisy fleabane, with syrphid fly pollinator |
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hood of Darlingtonia Pitcher Plant, a carnivore & perch for a California Dancer damselfly |
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Indian Pipe, a parasite on mycorrhizal fungi
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Rue Anemone, spring wildflower |
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Mountain Lupine, wildflower at altitude |
Hepatica, spring wildflower |
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Milkweed, friend to Monarch Butterflies |
Marsh Marigold, semi-aquatic wildflower |
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rabbitsfoot clover |
Great Blue Lobelia, wildflower |
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waxy bells of Dogbane, wildflower |
Skunk Cabbage flower inside its protective hood |
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Indian Paintbrush in Panther Meadow, Mt. Shasta, CA |
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maple leaves, deciduous native tree |
unidentified seaside succulent in flower |
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Field Bindweed, native wild vine |
honeysuckle vine |
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Tall Sunflower, native wildflower |
Staghorn Sumac, woody native shrub |
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Thistle flowers, native wildflower |
Wild Cherry tree in blossom |
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