Root · Stem · Leaf · Inflorescence · Flower · Fruit · Seed · Families
The root is the usually underground, non-green descending part that anchors the plant and absorbs water & minerals.
| Type | Origin | Found in |
|---|---|---|
| Tap root | Develops from the radicle; one main root with branches | Dicots (mustard) |
| Fibrous root | Many roots from the base of the stem | Monocots (wheat) |
| Adventitious | Arise from parts other than the radicle | Banyan, grass, Monstera |
The stem is the ascending axis bearing nodes, internodes, buds, leaves, flowers & fruits; it develops from the plumule. (Tip: nodes & buds tell a stem from a root.)
| Modification | Form | Examples |
|---|---|---|
| Underground (storage, perennation) | Tuber, rhizome, corm, bulb | Potato (tuber), ginger (rhizome), Colocasia (corm), onion (bulb) |
| Subaerial (vegetative propagation) | Runner, stolon, offset, sucker | Grass (runner), strawberry, Pistia/Eichhornia (offset), mint (sucker) |
| Aerial | Stem tendril, thorn, phylloclade | Cucumber/grapevine (tendrils), Citrus/Bougainvillea (thorns), Opuntia (phylloclade) |
The leaf is a flattened lateral outgrowth of the stem borne at a node; it is the chief organ of photosynthesis. Parts: leaf base, petiole, lamina.
| Type | Description | Example |
|---|---|---|
| Simple | Lamina entire or incised but not reaching the midrib | Mango, guava |
| Pinnately compound | Leaflets along a common axis (rachis) | Neem |
| Palmately compound | Leaflets attached at a common point (petiole tip) | Silk cotton |
An inflorescence is the arrangement of flowers on the floral axis. Two main types:
| Type | Growth of main axis | Flower opening order |
|---|---|---|
| Racemose | Continues to grow; flowers borne laterally | Acropetal â older below, younger above |
| Cymose | Tip ends in a flower; limited growth | Basipetal â older at top/centre, younger below |
The flower is the reproductive unit. Four whorls on the thalamus: calyx (sepals), corolla (petals), androecium (stamens), gynoecium (carpels). Calyx + corolla are accessory; androecium + gynoecium are reproductive.
| Term | Ovary position | Example |
|---|---|---|
| Hypogynous | Superior ovary; other parts below | Mustard, china rose |
| Perigynous | Half-inferior; parts at the rim, ~same level | Rose, plum |
| Epigynous | Inferior ovary; parts above | Guava, cucumber, sunflower |
| Type | Description | Example |
|---|---|---|
| Marginal | Ovules on the ventral suture, one chamber | Pea |
| Axile | Placenta axial, ovules in chambers | Tomato, lemon, china rose |
| Parietal | Ovules on inner wall / false septum | Mustard, Argemone |
| Free central | On central axis, no septa | Dianthus, Primrose |
| Basal | Placenta at base, single ovule | Sunflower, marigold |
A fruit develops from the ovary after fertilisation. Wall = pericarp (epicarp + mesocarp + endocarp). A true fruit develops from the ovary only; a false fruit involves the thalamus too (apple).
| Dicot seed (gram/bean) | Monocot seed (maize) | |
|---|---|---|
| Cotyledons | Two, often store food | One; endosperm stores food |
| Special parts | Plumule, radicle, hilum, micropyle | Scutellum, coleoptile, coleorhiza, aleurone layer |
| Fabaceae (pea) | Solanaceae (potato) | Liliaceae (lily) | |
|---|---|---|---|
| Root | Tap, root nodules | Tap | Fibrous (monocot) |
| Calyx/Corolla | K5 (united) · C5 papilionaceous (1 standard, 2 wings, 2 keel) | K(5), C(5) united | Perianth P3+3 (tepals) |
| Androecium | A(9)+1 (diadelphous) | A5, epipetalous | A3+3 |
| Gynoecium | Monocarpellary, superior, marginal | Bicarpellary, syncarpous, superior, axile, obliquely placed | Tricarpellary, syncarpous, superior, axile |
| Aestivation | Vexillary | Valvate | Valvate |
| Examples / uses | Gram, pea, groundnut (pulses, dyes, fodder, Nâ-fixing) | Tomato, potato, brinjal, tobacco, belladonna (food, medicine) | Onion, garlic, tulip, Aloe, Colchicine |
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