Lecture 8 - Angiosperm (Basal and Magnoliids)

• Angiosperms


  Plants that produce flowers and bear seeds covered within a fruit

  
• Angiosperms are VULNERABLE (IUCN)
• Parts of an angiosperm flower

  • Spadix
  • Spathe
  • Calyx
  • Sepal
  • Petal
  • Perianth (corolla + calyx)
  • Stamen
  • Carpel (pistil)
  • Gynoecium

  
• Economic importance of angiosperms

  • Food: grains, beans, nuts, fruits, vegetables
  • Herbs and spices
  • Beverages: tea, coffee, chocolate, wine, beer, tequila, and cola
  • Clothing: cotton, linen, rope, burlap, commercial dyes
  • Drugs: aspirin, digitalis, atropine, opium, cocaine, marijuana, tobacco
• Inflorescence


  A cluster of flowers

  
• Corona


  An additional structure in some flowers that functions in pollination, located where the nectaries are situated

  
• Tepal


  When a flower has no distinct petals and sepals

  
• Bract


  Leaf-like structure associated with flowers and fruits, for protection and attraction
• Involucre


  A series of bracts beneath or around a flower, in a whorl or rosette form surrounding an inflorescence

  
• Types of flowers according to the corolla

  • Sympetalous
  • Apocarpous (with free/separate carpels)

  
• Synandrous


  Fused stamens
• Adnation


  Fusion between floral parts of a different kind or whorl
• Types of ovary


  • Inferior
  • Half-inferior
  • Superior
• Placentation


  • Parietal (placenta on outer wall)
  • Axile (placenta at center where carpels meet)
  • Free central (single chamber, central placenta)
  • Basal (single ovule linked to base of ovary)
• Flower types


  • Complete (has all 4 floral parts)
  • Incomplete (missing one or more floral parts)
  • Perfect (has androecium and gynoecium)
  • Imperfect (missing androecium or gynoecium)
  • Carpellate/Pistillate (imperfect, has carpels/pistils only)
  • Staminate (imperfect, has stamens only)
  • Monoecious (has both carpellate and staminate flowers on same plant)
  • Dioecious (one plant has only staminate, another has only carpellate flowers)
  • Hermaphrodite (has both male and female parts)

  
• The Cronquist System is a taxonomic classification system of flowering plants (Magnoliophyta) developed by Arthur Cronquist

  
• The Cronquist System places flowering plants into two broad classes, Magnoliopsida (dicotyledonous) and Liliopsida (monocotyledonous)

  
• Double fertilization


  One sperm nucleus unites with egg, other sperm nucleus unites with polar nuclei to form endosperm
• Major angiosperm clades


  • Basal: Amborellales, Nymphaeales, Austrobaileyales
  • Magnoliids: Laurales, Magnoliales, Piperales
• Characteristics of basal angiosperms

  • Lack differentiation between petals and sepals (tepals)
  • Have little fusion within floral parts
  • Tend to have multiple, flattened stamens and multiple carpels
  • Fruits are typically single-chambered and dry
  • Have a less advanced vascular system than other angiosperms

  
• Amborella


  A dioecious, tropical shrub considered the most basal angiosperm
• Nymphaeales


  Order consisting of Nymphaeaceae (water lily family) and Cabombaceae
• Nymphaeaceae


  • Aquatic, annual or perennial herbs with milky latex, rhizomatous or tuberous stems, simple peltate leaves, solitary floating or emergent flowers, numerous spiral stamens, syncarpous gynoecium, berry fruit

  
• Cabombaceae


  • Aquatic plants living in still or slow-moving waters, two genera: Brasenia and Cabomba
• Austrobaileyales


  Order including Illiciaceae (star anise family) and Trimeniaceae
• Illiciaceae


  • Evergreen trees or shrubs with aromatic oil cells, spiral leaves, flowers with numerous spiral tepals, few-numerous stamens, apocarpous pistils in a single whorl, fruit a follicetum

  
• Trimeniaceae


  • Small family of one genus, Trimenia, with 8 species of woody plants bearing essential oils
• Magnoliids


  Large group of basal angiosperms including trees, shrubs, herbs and vines, most common in tropical and warm temperate regions

  
• Laurales


  • Perennial trees or shrubs with aromatic oil glands, evergreen leaves, undifferentiated perianth, valvular anther dehiscence, single superior ovary with one ovule, seeds lacking endosperm
• Magnoliales


  • Order including Annonaceae (custard-apple family) and Magnoliaceae, distinctive in having trees, shrubs or vines with simple distichous leaves, trimerous perianth, numerous spiral stamens and pistils, seeds with ruminate endosperm

  
• Piperales


  • Order including Piperaceae (pepper family), herbs, shrubs, vines or trees with atactostelic stem, spike inflorescence with small unisexual or bisexual flowers lacking perianth, solitary 1-ovulate ovary, fruit a berry or drupe
• Canellales


  • Order including Canellaceae and Winteraceae, fragrant trees and shrubs with leathery alternate leaves, flowers with 3 sepals, 4-12 petals, 6-40 united stamens