Floral Morphology

This lab covers floral morphology: the structure and shapes of flowers

Parts of a Flower

• Pedicel - the stalk of an individual flower
• Whorl: a cyclic group in a flower. The four whorls are the calyx, the corolla, the androecium, and the gynoecium.
• Calyx - the sepals collectively.
  • Sepal - one member of the outermost whorl of a flower. Collectively, the sepals make up the calyx. The sepals may be free or fused.
• Corolla - the petals of the flower
  • Petal - one member of the second whorl of a flower. Collectively, the petals make up the corolla. The petals may be separated or fused into one piece.
    • Dicots usually have 4 or 5 petals or multiples of 4 or 5.
    • Monocot usually have 3 petals or multiples of 3 petals.
• Androecium - the male sporophyll within the flower, one of the four whorls.
  • Stamen - one member of the whorl of male sex parts. Each stamen consists of a filament and anther, where pollen is produced. Collectively, the stamens make up the androecium.
  • Anther - structure containing pollen
• Gynoecium - the innermost whorl, the portion referred to as the female sporophyll.
  • Carpel - one member of the whorl of female sex parts. Collectively, the carpels make up the gynoecium. Each carpel consists of an ovary connected to a stigma by a style. The stigma is receptive to pollen. Within the ovary the seeds form.
  • Stigma - the sticky receptive surface for the pollen
  • Style - the stalk between the stigma and ovary. The whole unit is also refered to as the pistil.
• Perfect flower - having both stamens and pistils
• Complete flower - having sepals, petals, stamens, and pistils (all four whorls).
• Monoecious - stamens and pistils on one plant
• Dioecious - staminate and pistillate flowers on different plants (e.g. papaya)

Corolla Shapes

• Bilabiate - two lipped as in some members of fabaceae, zygomorphic
• Campanulate - bell shaped
• Funnelform - funnel shaped
• Ligulate - the ray floret on a head
• Papilionaceous - butterfly shape
• Rotate - flattened round disk
• Slaverform - tubular base flaired sharply at top
• Spurred - having a spur

Inflorescence Types

For each, the stalk of the inflorescence is called the peduncle and the stalk of an individual flower is the pedicel.

• Solitary - just one flower on the peduncle
• Spike - one unbranched axis and the flowers sessile (without pedicels)
• Spadix - like a spike, but fleshy and the flowers usually reduced and unisexual. Often subtended by a bract called a spathe.
• Spikelet - like a spike, but with the flowers and inflorescence subtended by specialized bracts. Usually applied to the grass family.
• Raceme - one unbranched axis and the flowers with pedicels
• Corymb - like a raceme, but the pedicels all elongating to the same level to give the inflorescence a flat-topped appearance.
• Umbel - all the pedicels arise from one point at the top of the peduncle
• Verticil or Whorl - the flowers are borne in a tight circle at each node
• Panicle - the main axis has branches which are in turn rebranched
• Head - many small flowers borne on a common receptacle; may look like a single flower. Common in the sunflower family (Asteraceae)

Ethnobotany • Botany • Lee Ling • COMFSM