Figure 10.25: Angiosperms are the flowering plants. ( 16 )Even though flowers may differ widely in their appearance, they do have some structures
in common. The outermost structure is thesepals,collectively known as thecalyx,which
are usually green and protect the flower before it opens. The petals, collectively known as
thecorolla,are often bright and colorful to attract a particular pollinator, an animal that
carries pollen from one flower to another. The next structure is thestamens,consisting of
the stalk-likefilamentthat holds up theanther,or the pollen sacs. The pollen is the male
gametophyte. At the very center is thecarpel,which is divided into three different regions:
the sticky, knob-likestigmawhere the pollen lands, the slender tube of thestyle,and the
enlarge base known as theovary. The ovary is where the ovules, the female gametophytes,
are found. When the ovules are fertilized, the ovule becomes the seed and the ovary becomes
the fruit. Some flowers have all these parts and are known ascomplete flowers(Figure
10.26), while others may be missing one or more of these parts and are known asincomplete
flowers.
Table 10.1:Flower part Definition
sepals Outermost layer of the flower that is usually
leaf-like and green.
calyx The sepals collectively; outermost layer of
the flower.
corolla The petals of a flower collectively.
stamens The part of the flower consisting of a fila-
ment and an anther that produces pollen.