Biology Today - February 2018

Types of

gamopetalous

corolla

Corolla is funnel-

shaped, HJ'DWXUD

Corolla is like bell or inverted

cup, HJ&DPSDQXOD

Tube of the corolla is

narrow and short and the

limbs are at right angles

to the tube,HJ., brinjal.

Tubular corolla with spreading

lobes, HJ, &OHURGHQGURQ

Infundibuliform

Rotate or wheel shaped

Salver shaped or hypocrateriform

Campanulate

Corolla is divided into two lips-the

upper lip and lower lip with the mouth

gaping wide open, HJ., 2FLPXP

Corolla is tubular

or cylindrical, HJ

central florets

of Sunflower.

The upper part of corolla is

flattened like a strap with

the lower part forming

a short-tube, HJ, outer

florets of Sunflower.

Corolla is bilabiate but

the lips are so near to

each other as to close

the mouth of the corolla,

HJ$QWLUUKLQXP

Spinous

Spinous

Spinous

Bilabiate

Tubular

Ligulate or strap-shaped

Personate or masked

AESTIVATION

• The mode of arrangement of sepals or petals with respect to one another in the floral bud is termed as aestivation.

Twisted or contorted

One margin of each petal overlaps the margin of an adjacent

petal and the other margin being overlapped by margin of

another adjacent petal, HJ+LELVFXVURVDVLQHQVLV

Quincuncial

Aestivation of 5 parts, where two are exterior,

two interior and the fifth is having one margin

exterior and the other interior.

Valvate

Margins of adjacent sepals or petals or

tepals just touch each other without any

overlapping, HJ%UDVVLFD

Descending imbricate or vexillary

The standard petal is large and overlaps the

two wing petals which in turn overlap the

keel petals, HJ Sub-family Papilionaceae.

Ascending imbricate

Aestivation of five parts, where one is exterior, one is

interior and rest three are having one margin exterior

and other interior.

Types of

aestivation

ANDROECIUM

• Androecium is the third whorl made up of stamens or microsporophylls. Each stamen consists of filament, anther and connective.


• Stamens may be borne directly on the thalamus or fused with petals (= epipetalous, H.J., 6RODQXP, 3HWXQLD) or tepals
  (= epiphyllous or epitepalous, H.J., $VSKRGHOXV).


• In majority of angiosperms, anthers are two lobed or dithecous. Each anther lobe consists of two pollen sacs (or microsporangia).
  Thus a typical dithecous anther is always tetralocular (or tetrasporangiate).


• In members of Family Malvaceae, anthers are monothecous. Pollen grains (or microspores) are produced in the microsporangium.
  Fusion of stamens with a dissimilar organ is called adhesion while fusion with a similar organ is known as cohesion.

Types of

cohesion

between

stamens

Syngenesious

Stamens

are fused by

anthers only;

filaments are

free, HJ

+HOLDQWKXV

DQQXXV Syngenesious

Adelphous

Stamens are fused by their

filaments only; anthers are free.

Fusion of filaments may produce

a single group (monadelphous,

HJ+LELVFXV), two groups

(diadelphous, HJPea), or many

groups (polyadelphous, HJ&LWUXV).

Synandrous

Stamens

are fused by

both their

filaments

as well as

anthers, HJ

&XFXUELWD.