20.2 Classification of Plants Seedless Nonvascular Plants.
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20.2 Classification of Plants Seedless Nonvascular Plants
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Transcript of 20.2 Classification of Plants Seedless Nonvascular Plants.
20.2 Classification of Plants
Seedless Nonvascular Plants
20.2 Classification of Plants
Seedless Non-Vascular Plants Three groups
mosses
Leafy liverwort
hornwort
20.2 Classification of Plants Evolutionary Relationships
Green Alga
Other Bryophytes
20.2 Classification of Plants
Seedless nonvascular plants.
• Nonvascular plants grow close to the ground to absorb water and nutrients.
• Most abundant in humid, temperate or tropical regions
• Usually no conductive tissue, sometimes poorly developed tissue
20.2 Classification of Plants
• Seedless plants rely on free-standing water for reproduction.
• NEED MOIST ENVIRONMENT, when active
• Mosses reproduce by branching and fragmentation, by regeneration from tiny pieces of leaves or stems, and by the production of spores.
• The spore, under favorable conditions, germinates and grows into a branching green thread.
20.2 Classification of Plants
Seedless nonvascular plants.
– Liverworts- often grow on wet rocks or
in greenhouses- can be thallose or leafy
20.2 Classification of Plants
• Hornworts
– found in tropical forests and along streams
– flat, lobed body with little green “horns”
20.2 Classification of Plants
• Mosses
– most common seedless nonvascular plants– There are approximately 12,000 species of moss
classified in the Bryophyta– sphagnum moss commonly used by humans as “peat”
20.2 Classification of Plants
Many small plants bearing the name moss are in fact not mosses.
• The “moss” found on the north side of trees is the green alga Pleurococcus; Irish moss is a red alga.
• Beard lichen (beard moss), Iceland moss, oak moss, and reindeer moss are lichens.
• Spanish moss is a common name for both a lichen and an air plant of the pineapple family (Bromeliaceae).
• Club moss is a fern ally in the family Lycopodiaceae.
20.2 Classification of Plants
• Mosses existed as early as the Permian Period (299 to 251 million years ago), and more than 100 species have been identified from fossils of the Paleogene and Neogene periods (65.5 to 2.6 million years ago). (yes they are older than dinosaurs)
20.2 Classification of Plants
Importance of moss
• Mosses break down exposed substrata, releasing nutrients for the use of more complex plants that succeed them.
• They aid in soil-erosion control by providing surface cover and absorbing water, and they are important in the nutrient and water economy of some vegetation types.
• Know as pioneer species. (first organism to inhabit an area)
