Question

Why are ray florets called neuters?

Answer 1

Ray florets are a part of an inflorescence which is a characteristic feature of the Asteraceae family or sunflower family. A unique type of inflorescence is observed where the flower head is composed of many minute flowers with two different sets on the inner side and periphery.

Complete step by step answer:
- Capitulum inflorescence is one of the characteristics of the Compositae or Asteraceae family. E.g. Tagetes (Marigold), Helianthus (Sunflower).
- Ray florets and disc florets are a part of capitulum or racemose head inflorescence. Here, the receptacle bears small sessile flowers which are called florets. The receptacle is formed by the flattening of the peduncle.
- Florets on peduncles are arranged centripetally i.e younger ones near the center while older ones protrude on the periphery or outside. Two types of florets are present: ray florets and disc florets.
- The peripheral ray florets are neuters as both the male and female reproductive structures are absent. They appear to be petals of an individual flower but instead, they are itself a complete flower.
- Also, ray florets are zygomorphic while the central disc florets are bisexual and actinomorphic.

Additional Information: Some features of the Asteraceae family are as follows:
- The members of this family are herbs or shrubs. They are rare trees. Based on habitat, they are usually xerophytic e.g. Proustia or hydrophytes like Cotula.
- The Taproot system is most prominent, though, in some fibrous root systems can be observed e.g. goldenrod (Solidago).
- The leaves can be alternate, opposite, and rarely whorled. Leaves are situated i.e. stipules are absent.
- A whorl of bracts called involucre is present on either side of the inflorescence.
- Syngenesious condition is an arrangement of stamens where their anthers are fused while their filaments are free. The fused anthers form a circle around the gynoecium.

Note: Some important terms to remember:
- Inflorescence: The manner in which the flowers are arranged as well as distributed over a plant is known as inflorescence. The arrangement occurs on a peduncle which is the axis of inflorescence.
- Actinomorphic: When flowers are radially symmetrical i.e two equal halves will be obtained from any plane of an axis passing through the center.
- Zygomorphic: When flowers are bilaterally symmetrical or they produce equal halves only from one plane of the axis.