Types of Phyllotaxy: Phyllotaxy refers to the arrangement of leaves on the stem. Different types include:

• Alternate phyllotaxy: Leaves are arranged singly at each node, alternating along the stem. Example: Mango (Mangifera indica)
• Opposite phyllotaxy: Leaves are arranged in pairs at each node, opposite each other along the stem. Example: Guava (Psidium guajava)
• Whorled phyllotaxy: Leaves are arranged in groups of three or more at each node. Example: Oleander (Nerium oleander)

Definition of Aestivation and Placentation:

• Aestivation: Aestivation refers to the arrangement of floral parts (sepals, petals, etc.) in a flower bud before it opens. It can be valvate, twisted, imbricate, or vexillary.
• Placentation: Placentation refers to the arrangement of ovules within the ovary of a flower. It can be marginal, axile, parietal, or basal.

Difference Between Racemose and Cymose Inflorescence:

• Racemose inflorescence: In racemose inflorescence, the main axis continues to grow, producing flowers along its sides. Example: Mustard (Brassica juncea)
• Cymose inflorescence: In cymose inflorescence, the main axis terminates in a flower, and further growth is from lateral branches. Example: Bougainvillea (Bougainvillea spectabilis)

Labelled Diagram of a Gram Seed:
                                   _______________
                                  |      Plumule  |
                    ________      |________________|
                   |        |     |   Seed Coat   |
                   |        |_____|________________|
                   |        |_____|________________|
                   | Embryo |_____|________________|
                   |        |     |    Hilum      |
                   |        |     |________________|
                   |________|     |_______________ |  
                                  |   Radicle     | |
                                  |_______________|_|

Explanation:

1. Plumule: The embryonic shoot of the plant.
2. Seed Coat: The protective outer covering of the seed.
3. Embryo: The young plant contained within the seed.
4. Hilum: Scar left on the seed coat where it was attached to the plant.
5. Radicle: The embryonic root of the plant.
   
   

   Labelled Diagram of a Vertical Section (V. S.) of a Maize Seed:
                ___________________
               |      Endosperm     |
               |___________________|
               |                   |
               |    Embryo (Plumule)|
               |___________________|
               |                   |
               |    Embryo (Radicle)|
               |___________________|
               |                   |
               |     Seed Coat      |
               |___________________|
   

   Explanation:

   1. Endosperm: The nutrient-rich tissue surrounding the embryo.
   2. Embryo (Plumule): The embryonic shoot of the plant.
   3. Embryo (Radicle): The embryonic root of the plant.
   4. Seed Coat: The protective outer covering of the seed.