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

• Key characteristics for plant identification

Compound leaf

Leaf or Leaflet?

Simple leaf

Leaves

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

Dry fruits- nuts, legume

Fleshy fruits- berry, drupe, pome

• Key characteristics for plant identification

fruits