66 ^|

A Handbook of Biology



A sterile stamen is called staminode.



When stamens are attached to petals, they are epipetalous.E.g. Brinjal.

When stamens are attached to perianth they are epiphyllous. E.g. Lily.



If the stamens are free, it is called polyandrous. If they are united it is

called synandrous. It is of many types:



Monoadelphous: Stamens are united into one bunch or one bundle. E.g.

China rose



Diadelphous: Stamens are united into two bundles. E.g. Pea.



Polyadelphous: Stamens are united into more than two bundles. E.g.

citrus. (NEET 2016) There may be a variation in the length of filaments

within a flower. E.g. Salvia and mustard.

D. GÝÑØËÇÏÜM (PÏSTÏL)

The female reproductive part is made up of one or more carpels. A carpel

has 3 parts: Stigma, Style and Ovary

Stigma:

It is the receptive

surface for pollen

grains. It is usually at

the tip of the style.

Ovary:

It is the enlarged basal

part on which the style

lies. Each ovary bears

one or more ovules

attached to a flattened,

cushion-like placenta.

Style:

An elongated tube

that connects ovary to

stigma.

Polycarpellary pistils (pistil with many carpels) are of 2 types:

(a) Apocarpous: Carpels are free. E.g. Lotus and Rose. (AIPMT 2010)

(b) Syncarpous: Carpels are fused. E.g. Mustard and Tomato.

PLÅÇËÑTÅTÏØÑ

It is the arrangement of ovules within the ovary. It is of many types:

Marginal: Here, the placenta forms a ridge along the

ventral suture of the ovary and the ovules are borne on

this ridge forming two rows. E.g. Pea.

Parietal: Here, the ovules develop on the inner wall

of the ovary or on peripheral part. Ovary is one

chambered but it becomes two- chambered due to

the formation of the false septum. E.g. Mustard and

Argemone.

(NEET 2019)