Name: The Flowering Plants-Angiosperms
Uploaded: 2019-07-19
Duration: 18 min 19 s
Description: Angiosperms are the most recent or advanced plants of the plant kingdom. They bear flowers and enclose seeds in fruits. Their life cycle is complex with doub...

Question

What are the various types of thalamus in relation to position of various types of floral organs?

Accepted Answer

The swollen structure of the flower which lie at the tip of the pedicel and bears floral organs is called thalamus. There are three forms of thalamus as regards the insertion of pistil and other floral organs. These are hypogyny, perigyny and epigyny.

In hypogynous flowers, the gynoecium or ovary occupies the top position on the thalamus while other floral parts are situated below it. In such flowers, the position of the ovary is superior. E.g., China rose, mustard etc.

In epigynous flowers, the thalamus grows in the form of a flask around the ovary fusing with its wall. Only the style and stigma of the pistil is observable from the upperside. The other floral parts are situated at the top of the ovary. Hence, the ovary is inferior. E.g. Guava, Cucumber

In perigynous flowers, the thalamus is turned to form a cup-shaped structure. The ovary is located at the centre and other floral organs are arranged on the rim of the thalamus. The ovary here is half inferior. E.g. Plum, Pear, Rose.

What are the various types of thalamus in relation to position of various types of floral organs?

Important Questions on Morphology of Flowering Plants

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