WB01343_.gif (599 bytes)      Composite Flowers      WB01345_.gif (616 bytes)

Composite Flowers (Asteraceae) have many individual flowers inserted on a flatened, broad receptacle so that they appear to be one large flower. Sunflower is the prime example. This family was once called the Compositae.

SunflowerField240.jpg (42393 bytes)
Sunflowers (Helianthus) have Disk & Ray Flowers!

SunflrReceptacleLab.jpg (111912 bytes)
Diagram of Sunflower in Sectional View
DiskFlrDiag240Calyxetc.jpg (61781 bytes)    DiskFlrDiag240Anthers.jpg (43142 bytes)   DiskFlrDiag240Stigma.jpg (47183 bytes)
Diagrams of Helianthus Disk Flowers showing their major structures

DiskFlrGlassLab.jpg (28992 bytes)
Model of a Disk Flower:The Spine Like Structures comprise the Calyx and are called the Pappus.
?Perfect or Imperfect?

RayFlrGlassLab.jpg (29745 bytes)
Model of A Ray Flower which also has a Pappus.
?Perfect or Imperfect?

ChicoryRay.jpg (72886 bytes)
Some species like Cichory (Cichorium) have only Ray Flowers

DiskFlrsOnly.jpg (70107 bytes)
Some species may only have Disk Flowers

YellowFlrHoriz240.jpg (15028 bytes)
A Composite Inflorescence which looks like  one flower.

 SFlwrReceptacleLSMacro240.jpg (16239 bytes)
Composite Inflorescence split down the middle Note the many small flowers attached to the broad Receptacle
Erigeron240.jpg (18126 bytes)                                   ErigeronLowMagMicro.jpg (182285 bytes)
Erigeron sp.- One of my favorite Flowers - I think you can see why!!!!!!

ErigeronHIMagMicroDiskLab.jpg (82594 bytes)
Long section of Erigeron Disk Flowers

 ErigeronHIMagMicroLab.jpg (85108 bytes)
Erigeron Flowers Showing the Gynoecium, Androecium & Corolla

Composites frequently contain two types of Flowers.

The central flowers are called Zinnia.jpg (94387 bytes)Disk Flowers.
These are Actinomorphic.

    

The peripheral flowers may have Zygomorphic corollas (bilateral symmetry)  and resemble rays of the sun. Thus, they are called Ray Flowers.

WB01343_.gif (599 bytes)  WB01344_.gif (644 bytes)  WB01345_.gif (616 bytes)