Explain different types of racemose inflorescences.

Racemose Inflorescence is a type of inflorescence where the main axis grows indefinitely, and the flowers are arranged laterally along the axis, usually in a branched or unbranched form. 

The growth pattern is typically indeterminate, meaning the oldest flowers are at the base while new flowers continue to develop at the tip. Below are different types of racemose inflorescences:

1. Raceme

In a raceme, the flowers are borne on a simple, unbranched axis. The flowers are pedicellate (each flower has a stalk) and are arranged in an acropetal manner (oldest flowers at the bottom and youngest at the top).

Example: Radish, Mustard.

2. Spike

A spike is similar to a raceme but differs in that the flowers are sessile (without stalks). They are arranged along a single axis in an acropetal sequence.

Example: Wheat, Sugarcane.

3. Corymb

In a corymb, the flowers are arranged on short pedicels, but they form a flat or slightly convex shape. The outer flowers bloom first, while the central ones bloom later. The pedicels are of unequal lengths, ensuring that all the flowers are at the same level.

Example: Coriander, Carrot.

4. Umbel

An umbel consists of a cluster of flowers that arise from a common point at the tip of the peduncle. The pedicels (flower stalks) are of equal length, giving the inflorescence a flattened or spherical shape.

Example: Onion, Garlic.

5. Thyrse

A thyrse is a compound inflorescence where a main axis bears a raceme or a corymb that is further branched. The flowers are arranged in a more complex pattern.

Example: Lilac, Jasmine.

6. Catkin (Ament)

Catkin is a slender, cylindrical inflorescence, often pendulous, consisting of small, unisexual flowers. The flowers are usually wind-pollinated.

Example: Willow, Oak.

7. Panicle

A panicle is a branched, compound inflorescence where the branches bear smaller racemes or spikes. It is characterized by a more complex branching pattern.

Example: Rice, Millet.