Racemose Inflorescence
சிறுபூக்கதிர் மஞ்சரி
Do not confuse indeterminate growth with immortality. In racemose inflorescence, the floral axis never terminates in a flower, unlike the cymose type. This distinction is a high-yield trap in NEET morphology questions.
The idea
In racemose inflorescence, the main axis continues to grow indefinitely. Flowers are borne laterally in an acropetal succession, meaning younger flowers are at the apex and older flowers are at the base. This ensures a prolonged period of pollination. The arrangement is strictly centripetal in flat-topped types.
Why it matters
Continuous growth of the axis allows the plant to produce flowers over a longer period, increasing the chances of pollination.
NEET lens
NEET expects you to distinguish between acropetal and basipetal succession. Memorize the examples: Radish, Mustard, and Snapdragon are classic racemose types. If the question describes the oldest flower at the base, mark 'Racemose' immediately. Do not waste time; this is a direct recall question.
Clinical significance
Botanical architecture dictates resource allocation. If the apical dominance mechanism—analogous to hormonal regulation in human growth—fails, the plant loses its reproductive efficiency. Understanding this growth pattern is fundamental to studying plant hormones like auxins and gibberellins.
Introduction
Racemose inflorescence has an indeterminate (indefinite) growth — the main axis keeps growing and flowers open from base to apex (acropetal succession).
Core concept
Types: Raceme (stalked flowers on elongated axis — mustard). Spike (sessile flowers — Achyranthes). Catkin (spike with unisexual flowers — mulberry). Spadix (fleshy spike with spathe — Colocasia, banana). Corymb (flat top, different stalk lengths — Iberis). Umbel (all stalks from one point — carrot family). Capitulum/head (flat receptacle, sessile — sunflower). Cyme — NOT racemose.
Go deeper
Capitulum (head) in sunflower has two types of flowers: ray florets (outer, ligulate, zygomorphic, sterile/female) and disc florets (inner, tubular, actinomorphic, bisexual). This is a pseudanthium (false flower).
From Class 10
You know flowers can be arranged differently on a plant — single flowers or in groups called inflorescences. Racemose is one type.