Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The flower is the reproductive unit in angiosperms, consisting of four whorls: Calyx (sepals), Corolla (petals), Androecium (stamens), and Gynoecium (carpels/pistils).
Flower Symmetry: Actinomorphic (radial symmetry, e.g., Mustard, Chilli), Zygomorphic (bilateral symmetry, e.g., Pea, Gulmohur), and Asymmetric (e.g., Canna).
Aestivation: The mode of arrangement of sepals or petals in a floral bud. Types include Valvate (e.g., ), Twisted (e.g., China rose), Imbricate (e.g., Cassia), and Vexillary (e.g., Pea).
Placentation: The arrangement of ovules within the ovary. Types include Marginal (Pea), Axile (China rose, Tomato), Parietal (Mustard, Argemone), Free central (Dianthus, Primrose), and Basal (Sunflower, Marigold).
Fruit: A mature or ripened ovary developed after fertilization. A fruit formed without fertilization is called a parthenocarpic fruit (e.g., Banana). In Drupes (Mango, Coconut), the pericarp is differentiated into outer epicarp, middle mesocarp, and inner stony endocarp.
Seed Structure: A seed consists of a seed coat and an embryo. In dicots, the embryo has an embryonal axis and two cotyledons. In monocots, there is usually one cotyledon called the .
In monocot seeds (e.g., Maize), the plumule is enclosed in and the radicle is enclosed in . The outer covering of endosperm separates the embryo by a proteinaceous layer called the layer.
📐Formulae
💡Examples
Problem 1:
Identify the type of placentation where ovules develop on the inner wall of the ovary or on peripheral part, and the ovary is one-chambered but becomes two-chambered due to the formation of a false septum.
Solution:
Parietal Placentation
Explanation:
In parietal placentation (e.g., Mustard and ), ovules are attached to the inner wall. The false septum that makes the ovary two-chambered is known as the .
Problem 2:
A flower of the family Fabaceae shows a specific petal arrangement. Describe the components of .
Solution:
Vexillary Aestivation: 1 Standard, 2 Wings, and 2 Keel (fused).
Explanation:
In Vexillary aestivation, the largest petal is the Standard (), which overlaps two lateral wings (), which in turn overlap the two smallest anterior petals called the Keel (), which are fused.
Problem 3:
In a Coconut fruit, which part of the pericarp is fibrous?
Solution:
The Mesocarp.
Explanation:
Coconut is a drupe. Unlike Mango where the mesocarp is fleshy and edible, the mesocarp in Coconut is highly fibrous, while the endocarp is stony and hard.