SC: Asteridae Order: Asterales Family: Asteraceae “Composites, Sunflowers”

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”