Definition: Transfer of pollen grains from anther to stigma.
Types:
- Autogamy (Self-pollination): Pollen from same flower (e.g., wheat, rice).
  - Cleistogamous flowers: Never open, always self-pollinated (e.g., Viola, Oxalis).
- Geitonogamy: Pollen from different flower on same plant (genetically self-pollination, ecologically cross-pollination).
- Xenogamy (Cross-pollination): Pollen from different flower on different plant of same species.
Agents of Pollination:
- Abiotic: Wind (anemophily), Water (hydrophily).
- Biotic: Animals (zoophily) - insects (entomophily), birds (ornithophily), bats (chiropterophily), etc.
Outbreeding Devices: Mechanisms to discourage self-pollination and encourage cross-pollination.
- Dichogamy (anther and stigma mature at different times).
- Herkogamy (physical barrier between anther and stigma).
- Self-incompatibility (genetic mechanism preventing self-pollen germination).
- Unisexuality of flowers (dioecy).

Recognition of compatible pollen.
Pollen germinates on stigma, forming a pollen tube.
Pollen tube grows through the style towards the ovule, entering through the micropyle.
Pollen tube discharges two male gametes into one of the synergids.

Unique to flowering plants.
Syngamy (True Fertilisation): One male gamete ($n$) fuses with the egg cell ($n$) to form a diploid zygote ($2n$).
Triple Fusion: The other male gamete ($n$) fuses with the diploid secondary nucleus ($2n$, formed by fusion of two polar nuclei) to form the triploid Primary Endosperm Nucleus (PEN, $3n$).

Zygote develops into Embryo.
Primary Endosperm Nucleus (PEN) develops into Endosperm (nutritive tissue).
- Types: Nuclear, Cellular, Helobial.
Ovule develops into Seed.
Ovary develops into Fruit.
Ovary wall develops into Pericarp (fruit wall).
Other floral parts (sepals, petals, stamens, style, stigma) usually wither and fall off.

Occurs at the micropylar end of the embryo sac.
Zygote $\rightarrow$ Proembryo $\rightarrow$ Globular $\rightarrow$ Heart-shaped $\rightarrow$ Mature embryo.
Dicot Embryo: Embryonal axis, two cotyledons.
- Epicotyl: Above cotyledons, terminates in plumule (shoot tip).
- Hypocotyl: Below cotyledons, terminates in radicle (root tip), covered by root cap.
Monocot Embryo: Single cotyledon (scutellum).
- Protective sheaths: Coleoptile (plumule), Coleorhiza (radicle).

Fertilised ovule. Contains embryo, food reserve, protective seed coat.
Non-albuminous (Exalbuminous) seeds: No residual endosperm (e.g., pea, groundnut). Food stored in cotyledons.
Albuminous seeds: Retain a part of endosperm (e.g., wheat, maize, castor).
Perisperm: Remnant of nucellus in some seeds (e.g., black p