Asteraceae

Overview

This lesson contains information about the Asteraceae family.

Flower, Fruit, Foliage and Form

Flower:

• Head of many (composite) small sessile (not stalked) flowers (florets)
• Florets perfect
• Aggregated (clustered) on common receptacle
• Surrounded by involucral bracts
• Outermost florets mature first, center ones last ( indeterminate )

• Ray florets:
  • Corolla tubular only at base; expanded upward into prominent ligule
  • No stamens, floret is functionally pistillate
• Disk florets:
  • Regular, tubular corolla
  • Usually normal and perfect
• Ligule florets:
  • Corolla expanded to one side in a ligule
• Flower heads composed only of ligulate florets are ligulate heads
• Flower heads composed only disk florets are discoid heads
• Flower heads composed only disk florets in center and ray florets around margin are radiate heads
• Heads are single or in a panicle or corymb

radiate head	ligulate head	discoid head

This animation will help to depict the different flowers that compose the inflorescences of the plants in the Asteraceae family. After viewing this animation, you should have a better understanding of the differences between ligulate, discoid and ray flowers.

Fruit:

• Achene—dry, indehiscent (not splitting open) capsule

 Form:
Annual, perennial, or biennial herbs and occasionally shrubs.
A basal rosette is often formed at the base of the plant (daisy) but leaves may (coneflower) or may not (rudbeckia) be present on the stem.

basal rosette		coneflower (Echinacea)

Leaves:

• Type: simple, rarely compound
• Arrangement: alternate, opposite, rarely whorled. Leaves sometimes opposite below and alternate above. Exstipulate (no stipules)
• Margins: various, entire to toothed, dissected, occasionally compound

Stems:
Stems maybe hollow or solid and contain a milky white sap. Stems may also be prickly or pubescent.

Roots:
Roots may be found near the surface (daisy) or a deep taproot (dandelion.)

Uses

Groundcovers

Antenneria parvifolia

Cutting flowers or foliage

Artemisia frigida

Background plants

Eupatorium maculatum

Accents

Aster novae-angliae

Borders

Achillea millefolium ’Paprika’

Naturalized areas

Echinacea

Winter interest

Rudbeckia fulgida var. sullivantii  ’Goldstrum’

Butterfly magnets, wildlife food and habitat

Echinacea x tennesseensis and Solidago

Grow it

Propagation

Propagation by division

Propagation by root cuttings

Propagation by stem cuttings

Propagation by seed

Pests, Diseases, and Environmental Effects

Variously susceptible to aster yellows or aster wilt, powdery mildew, rust, rabbit damage

Aster Yellows

Botrytis Blight

Downy Mildew
  

Powdery Mildew
   

Rhizopus Rot
 

Rust

Verticillium Wilt 
 

Drought Stress

                
Heat Stress

Leaf Curl

Link to University of Nebraska Department of Plant Pathology and Cooperative Extension

Plant List

Achillea filipendula
Achillea millefolium

Achillea tomentosa
Achillea x hybrid

Galaxy series

Anaphalis triplinervis
Antennaria dioica
Antennaria neglecta
Antennaria parlinii
Antennaria parvifolia
Anthemis tinctoria
Artemisia abrotanum
Artemisia absinthium
Artemisia frigida
Artemisia lactiflora
Artemisia ludoviciana
Artemisia schmidtiana
Artemisia stelleriana
Artemisia x

Aster alpinus
Aster divaricatus
Aster ericoides
Aster fendleri
Aster novae-angliae

Aster novi-belgii
Aster ptarmicoides
Aster x dumosus

Aster x frikartii
Boltonia asteroides

Catanache caerulea
Centaurea montanum
Chrysanthemum coccineum

Chrysanthemum pacificum
Chrysanthemum pacificum
Chrysopsis villosa
Coreopsis auriculata
Coreopsis rosea
Coreopsis tinctoria
Coreopsis verticillata

Dahlia x

Dendranthema zawadskii

Echinacea angustifolia
Echinacea pallida
Echinacea paradoxa
Echinacea purpurea

Echinacea x tennesseensis
Echinops ritro

Erigeron pumilus
Erigeron strigosus
Erigeron x

Eupatorium coelestinum

Eupatorium maculatum

Eupatorium perfoliatum
Eupatorium purpureum
Eupatorium rugosum
Gaillardia aristata
Gaillardia x grandiflora

Helenium autumnale

Helenium hoopsii
Helenium x
Helianthus annuus
Helianthus maximilianii
Helianthus petiolaris
Helianthus x multiflorus

Heliopsis helianthoides

Inula ensifolia

Kalimeris pinnafiida
Leucanthemum x superbum

Liatris apera
Liatris ligustylis
Liatris punctata
Liatris pycnostachya
Liatris spicata

Liatris squarrosa
Petasites japonicus
Ratibida columnifera

Ratibida pinnata
Rudbeckia fulgida

Rudbeckia hirta

Rudbeckia laciniata

Rudbeckia triloba
Solidago canadensis

Solidago rigida
Solidago speciosa
Solidago sphacelata

Solidago x

x Solidaster luteus

Stokesia laevis

Tanacetum parthenium