Semi Technical Description Of A Typical Flowering Plant

Overview Of Plant Families

Plant families represent an important part of the study of botany because they are a further classification system by which plants can be identified and studied and their uses utilised. Various plant families have different morphological and floral characteristics and, hence, are not only important for scientific studies but are also economically important in agriculture, medicine, and horticulture.

Three important plant families dealt with in this paper are the Fabaceae, Solanaceae, and Liliaceae. These three are cosmopolitan in distribution, though most of their species play vital roles in food, medicine, and decoration. Basic studies of their general features will introduce us to their ecological importance and worth to human civilisation.

Fabaceae Family (Leguminosae)

• Commonly known as the pea or legume family.

• Papilionoideae used to be a subfamily of Leguminosae.

• Cosmopolitan in distribution.

Vegetative Characters

• Habit: Trees, shrubs, herbs.

• Roots: Roots with root nodules which fix nitrogen.

• Stem: Erect or climber

• Leaves: Alternate, pinnately compound, or simple.

Floral Characters

• Inflorescence: Racemose - flowers are on a main axis.

• Flower: Bisexual, zygomorphic (or monosymmetrical)

Calyx

• Sepals: Five, gamosepalous- sepals united.

• Aestivation: Valvate or imbricate.

Corolla

• Petals: Five, polypetalous- petals free.

• Papilionaceous, that is, butterfly-like: A large posterior petal (standard), two lateral petals (wings), and two anterior petals forming a keel (enclosing stamens and pistil).

• Aestivation - vexillary, one big overlaps two lateral which in turn overlap the two smallest ones

Androecium

• Stamens - Ten, diadelphous.

• Anthers - Dithecous

Gynoecium

• Ovary - Superior, monocarpellary.

• Locule - Unilocular

Floral Formula

% K(5) C1+2+(2) A(9)+1 G1

• %: Zygomorphic flower.

• K(5): Five fused sepals

• C1+2+(2): Corolla is one posterior petal (called standard), two laterals (wings), two fused anterior (keel)

• A(9)+1: Nine are fused stamens and one is the free stamen

• G1: Superior ovary, monocarpellary

Economic Importance

• Pulses: Gram, arhar, moong, soybean

• Edible Oils: Soybean, ground.

• Widely distributed in tropical, subtropical, and temperate zones.

Solanaceae Family (Potato Family)

• Commonly known as the potato or nightshade family.

• Widely distributed in tropical, subtropical, and temperate zones.

Vegetative Characters

Mostly herbs, some shrubs, rarely small trees.

Stem

• Herbaceous, rarely woody.

• Aerial, erect, cylindrical, branched, solid or hollow, hairy or glabrous.

Leaves

• Alternate, simple, exstipulate (without stipules), venation reticulate.

Floral Characters

• Inflorescence: Solitary, axillary, or cymose (e.g., scorpioid cyme).

• Flower: Bisexual, actinomorphic (radial symmetry).

Calyx

• Sepals: Five, united (gamosepalous).

• Aestivation: Valvate.

Corolla

Petals: Five, united (gamopetalous), often forming a bell-shaped or funnel-shaped structure.

Aestivation: Valvate.

Androecium

• Stamens: Five, epipetalous (attached to petals).

• Anthers: Dithecous, often spirally twisted, and often forms a cone around the pistil.

Gynoecium

• Ovary: Superior, bicarpellary (two fused carpels), bilocular (two chambers).

• Placenta: Swollen with numerous ovules.

• Style: Simple, and the stigma is often capitate (head-like).

Fruit And Seed

• Fruit: Berry (e.g., tomato) or capsule (e.g., Datura).

• Seed: Numerous and endospermic.

Floral Formula

Formula: ⚥ K(5) C(5) A5 G(2)

• ⚥: Bisexual flower.

• K(5): Five fused sepals.

• C(5): Five fused petals.

• A5: Five stamens.

• G(2): Superior ovary, bicarpellary.

Economic Importance

Food Crops: Potato, tomato, brinjal (eggplant).

Spices: Chili pepper.

Medicinal Plants: Belladonna, ashwagandha.

Ornamentals: Petunia.

Tobacco: Nicotiana tabacum is used in the tobacco industry.

Liliaceae Family (Lily Family)

• Commonly known as the lily family.

• Distributed in temperate and tropical regions.

Vegetative Characters

• Habit: Mostly perennial herbs, with underground bulbs, corms, or rhizomes.

• Stem: Underground, modified (bulbs, corms, rhizomes).

• Leaves: Mostly basal, alternate or whorled, linear or lanceolate, with parallel venation.

Floral Characters

Inflorescence: Solitary, racemose, or umbellate.

Flower: Bisexual, actinomorphic.

Perianth

• Tepals: Six (3+3 arrangement), often petaloid, free or fused.

• Aestivation: Valvate or imbricate.

Androecium

• Stamens: Six, arranged in two whorls of three each.

• Anthers: Dithecous, basifixed.

Gynoecium

• Ovary: Superior, tricarpellary (three fused carpels), trilocular (three chambers).

• Ovules: Numerous on axile placentation.

• Style: Single, stigma trifid (three-lobed).

Fruit And Seed

• Fruit: Capsule or berry.

• Seed: Endospermic.

Floral Formula

Formula: ⚥ P3+3 A3+3 G(3)

• ⚥: Bisexual flower.

• P3+3: Six tepals in two whorls of three each.

• A3+3: Six stamens in two whorls of three each.

• G(3): Superior ovary, tricarpellary.

Economic Importance

• Ornamentals: Tulip, lily.

• Medicinal Plants: Aloe vera, Colchicum.

• Vegetables: Asparagus.

• Others: It finds its application in horticulture and landscaping.

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