reproducion of flowers

• Asexual reproduction


  Reproduction results in new individuals genetically identical to parent
• Sexual reproduction

  Reproduction results in progeny that differ genetically
• Some progeny may have combination of maternal and paternal genes


  Causes them to be better adapted than parents
• Floral whorls

  • Sepals (calyx)
  • Petals (corolla)
  • Stamen (androecium)
  • Carpel / Pistil (gynoecium)
• Stamen


  Male fertilizing organ of flower, consisting of pollen-containing anther and filament
• Carpel


  Female reproductive organ, consisting of ovary, stigma, and style
• Gynoecium composition

  • Monocarpous gynoecium
  • Apocarpous gynoecium
  • Syncarpous gynoecium
• Monocarpous gynoecium


  Single carpel
• Apocarpous gynoecium


  Multiple distinct ("unfused") carpels
• Syncarpous gynoecium


  Multiple connate ("fused") carpels
• Floral variation

  • Complete - all 4 whorls are present
  • Incomplete - lacking 1 or more of the whorls
  • Perfect - both stamen and pistil present (hermaphroditic)
  • Imperfect - either stamen or pistil is absent
  • Radial symmetry - divided into 2 equal halves along any plan
  • Bilateral symmetry - divided into 2 equal halves only by medial cut through central axis
  • Polypetalous
  • Gamopetalos
  • Apetalous
• Inflorescence parts

  • Peduncle - stalk of inflorescence
  • Inflorescence axes - branches of inflorescence
  • Flower bract - subtends individual flower
  • Inflorescence bract - subtends entire inflorescence/inflorescence axis
  • Involucre - group of inflorescence bracts subtending entire inflorescence
  • Spathe - specialized single inflorescence bract that subtends entire inflorescence
  • Spadix of araceae
• Inflorescence position

  • Terminal - develops from apical meristem of primary shoot / extended lateral branch with vegetative leaves
  • Axillary - develops from axillary bud of vegetative leaf, does not develop into extended branch system
• Inflorescence development

  • Determinate - terminal flower develops first
  • Indeterminate - basal flower develops first
• Sexual reproduction is important for evolution as it produces variable offspring creating diversity
• Variation is needed for Natural Selection
• Sexual reproduction is advantageous to an organism ONLY if it happens with someone other than itself
• 97% of plants are hermaphroditic
• Selfing (self pollination)


  10-15% of flowering plants, requires self compatibility, accompanied by structurally enforced mechanism (cleistogamous flowers)
• Methods to prevent self pollination

  • Dichogamy - Protandry, Protogyny
  • Unisexual flowers - Monoecious, Dioecious
  • Incompatibility - Produces chemical in stigma to prevent germination of own pollens
  • Heterostyly - Thrum-eyed, Pin-eyed
• Pollen grain


  Collection of microspores that assists with plant fertilization, produced by male structure
• Ovule


  Where female reproductive cells are made, turns into seed