Pollination, especially cross-pollination takes place by four different agents like insects, wind, animal and water. A short description of this stated below:
(1) Pollination through insects: In most.cases at the time of collection of Vnectar pollen grains from one flower is transferred to another flower by insects. Flowers in which pollination occur through insects are known as entomophilous flowers. Mustard, Basils, Orchids, Roses, Cucurbita, etc. are entomophilous flowers.
(2) Pollination through wind: In many plants Pollination occurs through the wind. Flowers in which pollination occur, through wind are known as Anemophilous flowers. Paddy, Wheat, Maize. Sugarcane, Palm etc, are Anemophilous or wind-pollinated flower.
Characteristic of Anemophilous flowers:
a). Flowers are usually unattractive and have inconspicuous colour
b). Flowers usually are without sweet scent and nectar.
c). Pollen grains are very light and are produced in large numbers.
d). Stigmas are large, feathery and sticky, so that pollen grains carried by wind may attach very easily.
(3) Pollination through Animals: In many flowers pollination occurs through Birds, Bat or Snails etc. Flowers which are pollinated by animals are called zoophilous flowers. Madar, Shimul, Kadam etc. are zoophilous flowers.
Characteristics of zoophilous flowers
(a) Flowers are usually large.
(b) Flowers have bright colour,
(4) Pollination through Water: Many aquatic plants are pollinated by water. When pollination is accomplished by water the flowers is said to be hydrophilous flowers. Vallisnerla, Urticularla etc. are Hydrophilous flowers.
Characteristics of hydrophilous flowers:
(a) Flowers are usually unscented.
(b) They grow under water.
(c) Female flowers are solitary and with long stalk.
(d) Male flowers are light, transferred by water through floating.