Biology Today - February 2018

Modification

of sepals

Pappus

Sepals modified

into hairy structure

which helps in

dispersal of fruits,

HJ Sunflower.

Spinous

In 7UDSD, the calyx

is persistent and

modified into

two spines.

Leafy and petalloid

In 0XVVDHQGD, one of

the sepals is modified

into a large leaf-like

Spurred coloured structure.

In Larkspur, from

the base of one of

the sepals arises a

tubular outgrowth

called spur.

Hooded

In $FRQLWXP, one

of the sepals is

modified into a

hood which covers

the whole flower.

COROLLA

• Corolla is the second whorl of a flower made up of petals. It may be polypetalous (petals free) or gamopetalous (petals
  fused).

Types of polypetalous corolla

Papilionaceous

Five unequal or irregular petals are arranged like a butterfly.

The posterior large bilobed petal called standard or vexillum,

overlaps the two smaller lateral petals named wings or alae. The

latter overlap the two anterior petals, which are fused laterally

by the upper anterior margins to form a boat shaped structure

called keel or carina. It is the characteristic of sub-family

Papilionaceae, HJ pea, bean, etc.

Cruciform

Four free clawed petals are arranged

diagonally or in the form of a cross, HJ

mustard, candytuft, etc.

Caryophyllaceous

Corolla consists of five petals with distinct

limbs and claws. The claw and the limb of

each petal remain more or less at right

angle to each other, HJ'LDQWKXV

Rosaceous

Five or more sessile or shortly clawed

petals are bent horizontally like a

saucer, HJ5RVDLQGLFD(rose).

Campanulate

Corolla is bell-shaped, HJ3K\VDOLV

477*3(::?00 ANSWER KEY

1. (d) 2. (b) 3. (c) 4. (b) 5. (d)


2. (d) 7. (a) 8. (c) 9. (c) 10. (d)


3. (d) 12. (b) 13. (b) 14. (b) 15. (b)


4. (c) 17. (c) 18. (a) 19. (b) 20. (d)


5. (d) 22. (b) 23. (b) 24. (d) 25. (d)


6. (b) 27. (c) 28. (d) 29. (c) 30. (c)


7. (c) 32. (d) 33. (a) 34. (d) 35. (d)


8. (c) 37. (b) 38. (d) 39. (c) 40. (a)