SC: Asteridae Order: Asterales Family: Asteraceae

1
SC Asteridae Order Asterales
Family Asteraceae Composites, Sunflowers

• 1. 22,000 species in 900 genera
• 2. Flowers (florets) are typically arranged in
  HEADS. Expanded Receptacle florets epigynous
  entire Head surrounded by an involucre of bracts
  phyllaries head is support by a flower stalk
  called the peduncle inferior
• Pappus bristles or scales (modified calyx)
• Corolla coalescence of petals
• Stamen 5 coalescent around style
• Pistil one 2 stigma lobes

2
SC Asteridae Order Asterales
Family Asteraceae Composites, Sunflowers

• Pappus bristles or scales (modified calyx)
• Corolla coalescence of petals
• Stamen 5 coalescent around style
• Pistil one 2 stigma lobes
• 3. Ray Flowers 3 of the coalesced petals
  elongate into a ligule.
• 4. Great variablity! Sterile, pistilate,
  staminate, perfect.

3
Tribes

• Chicory Tribe
• 1. Ray flowers only
• 2. Milky sap
• Lactuca wild lettuce, Taraxicum dandelion,
  Chicorium chicory

4
Tribes

• Ragweed Tribe -
• Monoecious staminate and pistillate flowers on
  same plant
• Ambrosia trifida giant ragweed, Ambrosia
  artemisifolia small ragweed

5
Tribes

• Aster Tribe -
• Style branches flattened in middle.
• Solidago goldenrods, Aster asters

6
Tribes

• Sunflower Tribe -
• 1. Both disc and ray flowers
• 2. Usually a crown of hairs at base of stigma
• 3. Pappus mostly bristle-like
• Helianthus sunflowers, Chrysanthemum ox-eyed
  daisy

7
Tribes

• Snakeroot Tribe -
• 1. disc flowers only
• 2. leaves mostly opposite
• Eupatorium rugosum white snakeroot, Liatris
  blazing star, Eupatorium purpureum Joe Pye
  weed, Eupatorium altissimum tall thoroughwort

8
Tribes

• Ironweed Tribe
• 1. Disc flowers only
• 2. Anthers sagittate
• 3. Stigma lobes long and pointed
• Veronia ironweed

9
Tribes

• Thistle Tribe
• Receptacle with a spiny involucre of bracts
• Cirsium vulgare bull thistle, Carduus nutans
  musk thistle