When calyx of a flower is joined together, it is called
Answer Details
The calyx is the outermost whorl of a flower, made up of individual units called sepals. When the sepals of the calyx are fused (joined together), the condition is described as gamosepalous.
The prefix gamo- means "united" or "fused," while sepal- refers to the sepals. So gamosepalous literally means "united sepals."
To distinguish the other terms:
Polysepalous describes a calyx in which the sepals are free (separate from each other). The prefix poly- here indicates "many separate" units.
Gamopetalous refers to fused petals (the corolla), not sepals. An example is the trumpet-shaped corolla of Datura.
Polypetalous describes a corolla in which the petals are free and separate.
A helpful memory aid: terms beginning with gamo- always indicate fusion, while those beginning with poly- indicate separate parts. The second half of the word tells you which floral part is involved: -sepalous for sepals, -petalous for petals.