Asteraceae (Sunflower family)

Asterid Eudicots

Leaf

Extremely variable
Leaves alternate or opposite
simple to bipinnate
estipulate

Sepals (Calyx)

Sepals modified into hairs, bristles, or scales
Form the pappus (aids in seed dispersal)
Persist on the fruit
Sometimes absent

Petals (corolla)

Flowers extremely small and packed into a head (capitulum)
Corolla can be regular or strap-shaped (ligulate)
Ligulate petals: 5 fused, flat, strap-shaped (in ray flowers)
Disc petals: 5 fused, forming a tube

Stamens

5 stamens
Anthers fused into a hollow tube
Surround the style

Pistil

a close up of a pink flower with drops o

Single pistil
Inferior ovary
Style with 2 branches

Ovary

Inferior ovary
Usually 1 ovule per ovary

Fruits

Tiny one-seeded achenes
Often called “seeds”
Usually have a pappus on top
Pappus helps with wind or animal dispersal

Photos

Sunflower

Sepals (Calyx)

Sepals modified into hairs, bristles, or scales
Form the pappus (aids in seed dispersal)
Persist on the fruit
Sometimes absent

Work Cited

“Sunflower (Helianthus Annuus), Leaves.” Feedipedia, www.feedipedia.org/content/sunflower-helianthus-annuus-leaves. Accessed 12 Dec. 2025.

“Sunflowers (Helianthus Annuus).” Love The Garden, Evergreen Garden Care (UK) Limited, 5 June 2024, www.lovethegarden.com/uk-en/growing-guide/how-grow-sunflowers.

4,854 Pistil Sunflower Images, Stock Photos, 3D Objects, & Vectors | Shutterstock, www.shutterstock.com/search/pistil-sunflower. Accessed 12 Dec. 2025.

Asteraceae | Characteristics, Inflorescence, Vegetables, Examples, & Facts | Britannica, www.britannica.com/plant/Asteraceae. Accessed 12 Dec. 2025.

Ohio Plants, ohioplants.org/families-asteraceae/. Accessed 12 Dec. 2025.

“Heliopsis Helianthoides - Sunflower-Everlasting.” Native Plant Trust: Go Botany, gobotany.nativeplanttrust.org/species/heliopsis/helianthoides/.Accessed 12 Dec. 2025.