Flower Inflorescences

1. Flower Inflorescences

2. Solitary and Inflorescence Flowers • Solitary: where only one flower is on the end of the stem (tulip, narcissus and roses). • Inflorescence: plants that have flower clusters; actually the branching system of the stem. • Peduncle – main stem of an inflorescence • Pedicel- branch from peduncle and support individual flowers

3. Determinate and Indeterminate • Determinate: the first flower to open is at the apex of the stem (liatris, kalanchoe and african violet). • Indeterminate: the last flower to open is terminal on the main axis (freesia, snapdragon, stock).

4. Racemose Inflorescences • The axis of the inflorescence continues to grow and the flowers are borne in the axes of the reduced leaves with the oldest flowers at the base and the newest flowers near the growing tip. • Raceme • Panicle • Spike • Spadix • Catkin • Corymb • Umbel • Head • Involucre

5. Inflorescence Types • Spike: elongated inflorescence with a central axis along which are sessile flowers; these lack pedicels • Gladioli, liatris, bottlebrush and copperleaf

6. Inflorescence Types Continued • Raceme: elongated inflorescence with a central axis along which are simple pedicels of more or less equal length • Snapdragon, delphinium, scotch broom, stock and allamanda

7. Inflorescence Types Continued • Panicle: elongated inflorescence with a central axis along which there are branches that are themselves branched (compound raceme). • Astilbe, begonia, crape myrtle and orange jessamine

8. Inflorescence Types Continued • Corymb: short and broad, flat-topped indeterminate inflorescence that has a main vertical axis and pedicels or branches of unequal length. With this the outer flowers open first. • Yarrow, candytuft and ixora

9. Inflorescence Types Continued • Umbel: inflorescence having several branches arising from a common point giving the inflorescence a knob-like look. A simple umbel consists of flowers with single pedicels. Compound umbels have secondary branching in the form of pedicels at the end of a ray. Outer flowers open first. • Queen Anne’s lace, amaryllis, dill and crinum lily

10. Inflorescence Types Continued • Spadix: a spike with a thickened, fleshy axis bearing the sessile with fleshy flowers close together, usually enveloped by a showy bract called a spathe. • Calla lily and anthurium

11. Inflorescence Types Continued • Catkin: a spike, raceme, or cyme composed of unisexual flowers without petals and falls as a unit at maturity (usually produces only staminate or pistillate flowers) • Willows, alders, oaks and birch

12. Inflorescence Types Continued • Head: rounded or flat-topped cluster of sessile flowers; include centrally grouped flowers called disc flowers encircled by ray flowers. • Gerbera daisy, chrysanthemum, sunflower, marigold, dahlia and strawflowers

13. Inflorescence Types Continued • Involucre: cluster or whorl of bracts or leaves directly under a flower or a cluster of flowers. Often found under umbels and heads. • Sunflower and cups of acorns

14. Cymose Inflorescences • The upward growth of the floral axis is stopped early by the development of a terminal flower. The first flower to open is at the tip with younger flowers appearing lower down on the axis. • Cyme • Scorpioidcyme • Fascicle

15. Inflorescence Types • Cyme: flat-topped inflorescence • Can be simple or compound • One terminal flower and two or more side flowers coming from the end of the axis. • Alstroemeria is a cyme; Baby’s breath is a compound cyme. • Frangipani and Brazilian nightshade

16. Inflorescence Types Continued • Scorpioidcyme: the floral axis curves over, carrying the flowers along the top of the curve. • Forget-me-nots

17. Inflorescence Types Continued • Fascicle: flowers are very closely crowded on almost the same plane • Sweet william