Question

Which of these is an example of a zygomorphic flower with imbricate aestivation?
a. Calotropis.
b. Mustard
c. Canna
d. Cassia
e. Cucumber

Answer 1

Hint: Arrangement in flowering plants where the accessory flowering organs are with one or the other floral bud is called aestivation. Most often the sepals and petals are organized. It is an arrangement of accessory floral organs with one another in the floral bud. Cassia is a flowering plant in the legume family Fabaceae.

Complete answer:
- Zygomorphic flowers are referred to as flowers in which the perianth segments within each whorl are bilaterally symmetrical about one vertical plane.
- In simple words, zygomorphic flowers are those flowers which can be divided into two similar halves by a single vertical plane or bilaterally symmetrical.
- Aestivation refers to the mode in which sepals or petals are arranged in a floral bud to other floral members.
- There are four types of aestivation in plants that include valvate, twisted, imbricate, and vexillary.
- The two lateral petals are overlapped by the posterior petal.
- There is irregular overlapping of petals e.g., Legumes. Posterior (lower part) petal being overlapped by the two lateral ones while they are being overlapped by the two anterior (upper part)
- In Calotropis then sepals in a whorl touch one another at the margin, without overlapping, it is said to be valvate aestivation.
- If one margin of the appendage overlaps that of the next one and so on as in china rose, lady’s finger, and cotton, it is called twisted.
- The aestivation is imbricated when the margins of sepals or petals overlap one another but not in any particular direction as in Cassia and Gulmohar.
- Calotropis is a genus of flowering plants in the family Apocynaceae and has valvate aestivation
- Mustard, belonging to the mustard family of plants, Brassicaceae (Cruciferae), and has twisted aestivation.
- Physiological features of Cassia include:
Habit: A medium-sized tree
Root: Tap branched,
Stem: Erect, woody, branched, cylindrical, glabrous, solid.
- Canna is the only genus of flowering plants in the family Cannaceae
- The cucumber is one of the members of the Cucurbitaceae family.

Hence, the correct answer is option (D).

Note: Cassia has medicinal properties it is used for diabetes, prediabetes, gas, obesity. In food and beverages, cassia is used as a flavoring agent. Hence zygomorphic flowers are those flowers that can be divided into two similar halves by a single vertical plane.