Question

What is hesperidium? Which one is called fibrous drupe?

Answer 1

Varieties of fruits are found in different species of plants. The ones that develop from a single ovary are known as simple fruits. These fruits are classified into 4 types including hesperidium and drupes.

Complete answer:
Fruits like orange, which have a and leathery skin and a very juicy inner ovary wall with several seeds are called a hesperidium. The peel if such fruits contain volatile oil glands in pits. The interior is separated into sections called carpels, filled with fluid-filled vesicles that are specialized hair cells.
A drupe is an indehiscent fruit with an outer fleshy part, either exocarp or mesocarp surrounding a single shell called the pit, stone, or pyrene of endosperm with a seed inside it. Examples of such fruits are mango, peach, black pepper, etc.

Additional Information: The fruit is the edible, seed-bearing structure of the plants. Some of them are juicy and sweet whereas others are sour. Some are seedless while some have one or more seeds present inside them. Fruit forms from a ripe ovary. It has two parts pericarp (three parts exocarp, mesocarp, and endocarp) and the seed.
The fruits that develop from a single matured ovary are called simple fruits. These are classified into:
-Drupes: Also known as stone fruits as it contains a hard, stone-like endocarp around the seed. Some examples are mango, plum, peach, etc.
-Berries: They have a single seed in the center. They are very juicy fruits such as grapes, blueberries, etc.
-Pome: These fruits bloom from trees such as papaya and apple.
-Hesperidium: These fruits have a very juicy interior which is separated into sections called carpels. Some examples are orange, lemon, lime, etc.
Along with simple fruits, three other types of fruits exist. These are aggregate fruits, multiple fruits, and accessory fruits.

Note: Generally, citrus fruits are Hesperidium, and fruits with tough seeds are considered as a drupe. The endocarp of a drupe is very tough. Therefore, the seed of these fruits is called pit or stone. Hesperidium has spongy skin with an interior separated in carpels. their skin has volatile oil glands. Both of these types developed from a single ovary. That's why they belong to the simple fruits.