Ordinarily, the flowers in a discoid head are all perfect (bisexual) and fertile. Thistles and ageratums are examples of Asteraceae species with discoid heads. The inner disk flowers generally are complete flowers, and the ray flowers generally are sterile.
Are ray flowers perfect or imperfect?
Ray florets are strap-shaped, imperfect, and never occur alone in the inflorescence (a condition referred to as heterogamous). They are always associated with disk florets (although disk florets may occur without ray florets), and form a circle around the margin of the head, the center filled with disk florets.
What is the difference between ray flowers and disk flowers?
Two main floret types are recognized: disc flowers (also written”disk”) and ray flowers. As shown in the photo at the right, of marigold’s two kinds of florets, disc flowers have cylindrical corollas, while ray flowers have flat, blade-like ones.
Are Asteraceae perfect or imperfect?
Also known as the Composite or Aster family. Usually herbs, some shrubs. Inflorescence a head (a group of flowers surrounded by involucral bracts). Flowers perfect or imperfect, radially symmetrical or bilaterally symmetrical.
Are Ray flowers regular or irregular?
description. …or more marginal rows of ray flowers, which have an irregular corolla. The corollas are tubular at the base but prolonged on the outer side into a generally flat projection, the ray, or ligule.
What makes a flower perfect?
A bisexual (or “perfect”) flower has both stamens and carpels, and a unisexual (or “imperfect”) flower either lacks stamens (and is called carpellate) or lacks carpels (and is called staminate).
What are some imperfect flowers?
Common examples of an imperfect flower that is monoecious are corn, birch trees, and walnut trees, while common dioecious plants include holly, willow trees, and poplar trees.
Is disc floret unisexual?
(a) Disc floret – The flowers which are present in the centre. They are actinomorphic and bisexual.
Is a ray floret a petal?
While it may look very much like one, a ray flower is not technically a petal as it is a complete flower bearing necessary sexual parts. What we most commonly refer to as a petal (or sometimes tepal) is the usually brightly colored part of the corolla immediately adjacent to but not part of the reproductive organs.
Are ray florets unisexual?
Ray florets are always unisexual pistillate or neuter in heterogamous head inflorescence. In homogamous head, these are bisexual.
Are all complete flowers perfect?
1. All complete flowers are perfect because they necessarily have both the stamen and pistil (examples: hibiscus, roses, beans, pea). 2. But not all incomplete flowers are imperfect because both the stamen and pistil may be present and what makes the flower incomplete is the absence of either sepal or pistil or both.
Is Marigold perfect or imperfect flower?
Flowers of these marigolds do not, technically, have sepals, so they are incomplete. In addition, they have disk and ray florets that may have only stamens (disk) or only carpels (ray) and, therefore, may be imperfect also.
Can a perfect flower be incomplete Why?
Complete flowers contain four flower parts: petals, sepals, stamen, and pistil. Incomplete flowers are missing one or more of these four parts. It is possible for a perfect flower to be incomplete, but it is not possible for an imperfect flower to be complete.
What is a disk flower?
Definition of disk flower
: one of the tubular flowers in the disk of a composite plant. — called also disk floret.
What is ray florets and disc floret?
Asteraceae species are characterized by having a capitulum, which is a compressed inflorescence consisting of two types of flowers: ray and disc florets. In the capitulum, disc florets are positioned in the center, surrounded by ray florets at the margin (Fig. 1, A–D).
Is Lavender perfect or imperfect?
Lavender plants have a perfect flower, they said, because it contained a stand that produces pollen for the pistol, and it has an ovary at the base where the eggs are produced.