pevolution • kidentification • pecology · • p lant diversity and evolution (groups of...
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Introduction to Plants and Plant Identification
• Plant diversity and evolution
• Key characteristics for plant identification
• Plant ecology
• Plant diversity and evolution (groups of plants)
• Plant evolution began 500 million years ago
• There are more than 280.000 species of plants
• There are four main groups of plants:
Bryophytes
Pteridophytes
Gymnosperms
Angiosperms
• Plant diversity and evolution (trends)
Bryophytes
(mosses)
Pteridophytes
(ferns)Gymnosperms
(Pines)
Angiosperms
(flowering plants)
time
• Complexity• Species Diversity• Adaptation to land
• Water budget
• Support
• Reproduction
• Plant diversity and evolution
liverworts
• Live in very humid environments and lack most of land adaptations
• Small plants without special structures for support
• Needs water for reproduction (flagellated sperm)
Bryophytes
hornwortsmosses
• Plant diversity and evolution
• Evolution of Cuticle and stomata
• Evolution of vascular tissue (xylem and phloem) with lignin in cell walls
• True roots, leaves and stems.
• Dispersion by spores (wing) but sperm still flagellated
Vascular plants
Pterydophytes
ferns horsetail
• Plant diversity and evolution
Seed plants
• Stronger lignin in cell walls
• Reproduction land adaptations:
Pollen
Seeds
Gymnosperms
ginkgo cycadsconifers
• Plant diversity and evolution
flowering plants
• Reproduction land adaptations:
Flowers (improve fertilization)
Fruits (improve dispersal)
• Two Classes: Monocots and Dicots
Angiosperms
• Angiosperms (flowering plants)
Monocotyledons
Linear leavesParallel venation
Growth at base of leavesNo vascular cambiumFibrous root systemFlower parts in 3xs
Dicotyledons
Leaves varied in shapeNet venation
Growth at terminal nodesVascular cambium
Taproot systemFlower parts in 4xs or 5xs
• Key characteristics for plant identification
Plant’s general appearance.Herbs- plants with non-woody aerial stemsShrubs- woody perennials with more than one stemTrees- woody perennial with just one stemVine- herbaceous plants with non-self-supporting stems
How long does the plant live?Annual- one year or lessBiennial- living for two yearsPerennial- living for three or more years
Placement of Leaves
Alternate - 1 leaf at a node
Opposite - 2 leaves at a node
Whorled - >3 leaves at a node
Leaves
• Key characteristics for plant identificationLeaf shapes
Leaf edges
EntireSerrateDentate
• Key characteristics for plant identification
Leaf venationParallelReticulatePinnatePalmate
Leaves
Leaf apicesAristateObtuse
Truncate
Leaf basesCuneateCordatePeltateClasping
• Key characteristics for plant identification
Number of petals
Monocot flowers- petals based on 3 Dicot flowers- petals based on 4 or 5
Flower shapeActinomorphicZygomorphicIrregular
flowers
Magnolia grandiflora(southern magnolia)
POLLINATION SYNDROMES
Generalist insects
(black walnut)
(princess-tree)
Wing-pollinated
Bee-pollinatedCarrion flowers
(crybabytree)
Hummingbird-pollinated
(Adam's needle)
Moth pollinated
http://www.cas.vanderbilt.edu/bioimages/pages/pollination.htm
Yucca filamentosaJuglans nigra
Paulownia tomentosa Dracunculus vulgaris Erythrina crista-galli