FLOWERS

Professor Joan S. Awingan

A flower is

the plant’s reproductive organ specializingin sexual reproduction

not a single organ, but is a branch bearingleaflike and stemlike parts on an axis

arises from the axil of the leaf

a typical flower consists of four whorls: calyx, corolla, stamen & pistil

Floral Parts

1. Pedicel – the stalk that holds the flower

2. Receptacle – somewhat enlarged tip of the pedicel from which the floral arise

3. Sepal – leaf-like structures that make up the outermost circle of the floral parts; usually green in color; protects the flower while it is still a bud

4. Calyx – collective term for all the sepals

5. Petal – one of the colored leaf-like structures that occurs in one or more circles within the sepals for attracting pollinators

6. Corolla – collective term for all the petals

7. Perianth - collective term for the sepals & petals

8. Pistil (carpel) – seed-bearing organ of the flower; usually pear-shaped and found at the center of the flower. It is composed of the ovary,

style, and stigma. Collectively called

GYNOECIUM

9. Ovary – enlarged basal part of the pistil with one morelocules (cavities containing ovules that develop into

seeds after fertilization)

10. Style – long and slender neck-like part extending from theovary and serves as passageway for thepollen from stigma to the ovary

11. Stigma – sticky part found at the tip of the style to which

pollen adheres after pollination

12. Stamen – the essential male part of the flower consistingof an

anther – where pollen grains are produced filament – slender stalk

that supports the anther

CLASSIFICATION OF FLOWERS

PRESENCE or ABSENCE OF FLORAL PARTS:

1.COMPLETE - sepal, petal, stamen, pistilEx: rose

2. INCOMPLETE

3. PERFECT – stamen & pistil (also called bisexual) but may lack sepals or petals

4. IMPERFECT – staminate or pistillate (unisexual)

KINDS OF INFLORESCENCE (clustering / grouping of flowers)

1. Spadix – a spike with a fleshy axis, enclosed by a large,often brightly-colored bract

Ex: Anthurium, calla lily

2. Catkin – a spike with a long and pendulous axis; bears unisexual flowers only

Ex: Buntot ng pusa (Acalypha hispida)

3. Umbel – the primary axis is shortened and bears at its tip a group of flowers which have pedicels of moreor less equal lengths, that they appear to spread out from a common point

4. Capitulum or Head - main axis is suppressed, becoming almostflat. The flowers (florets) are without stalk that they become crowdedtogether on the flat surface of the receptacle. The capitulum iscomposed of ray flowers along the margin and disk flowers crowded at the center of the flower

5. Cyathium – consists of a cup-shaped involucre formed by fused heads

ex: Euphorbia