Ch 3Vegetative Morphology — Class 11 Botany, concept-first.

Morphology is the study of an organism's various external features. Applied to plants, it is also called external morphology, and it examines the shape, size and structure of a plant's parts - its roo…

The general form or growth pattern of a plant is called its habit. Based on habit, flowering plants fall into four broad groups.

Depending on where a plant grows, its habitat is classed as terrestrial (land-growing) or aquatic (water-growing, i.e. hydrophytes).

Based on how long they live and complete their reproductive cycle, plants are grouped into three life-span categories.

Flowering plants (angiosperms, or Magnoliophytes) are sporophytes whose body is organised into an underground root system and an aerial shoot system.

The root is the non-green, cylindrical, descending axis of the plant that develops from the radicle - the first structure to emerge when a seed germinates in soil - and normally grows downward into th…

Roots are of two basic types depending on their origin. In the tap root system, found typically in dicotyledons, the primary root is a direct continuation of the radicle; it persists, keeps growing, a…

To perform secondary functions such as storage, respiration, mechanical support or absorption, roots often change from their normal cylindrical form - these changes are root modifications, grouped as…

The shoot system develops from the plumule of the germinating seed's embryo: the epicotyl elongates to form the stem axis, whose actively dividing apical meristem at the tip produces a mass of tissue…

A bud is a compressed growing point protected by scale leaves, in which the internodes have not yet elongated and the young leaves remain closed and crowded; as a bud develops, its internodes elongate…

Stems fall into three broad growth-habit groups. Most angiosperms have an upright, erect stem, of four kinds: excurrent, where the main axis grows continuously while lateral branches shorten progressi…

Stem modifications are grouped as aerial, sub-aerial or underground, depending on where the modified stem sits relative to the ground.

Leaves are the green, thin, flattened lateral outgrowths of the stem, and collectively all the leaves of a plant are called the phyllome.

A typical leaf has three parts: the leaf base (hypopodium), the petiole (mesopodium) and the lamina (epipodium).

Venation is the arrangement of veins and veinlets on the lamina, which internally carry the vascular tissue. It is broadly of two kinds.

Phyllotaxy (Greek phyllon = leaf, taxis = arrangement) is the pattern in which leaves are arranged on the stem, and it functions to avoid overcrowding while exposing the maximum leaf area to sunlight…

Leaf mosaic is the way leaves on a shoot fit together and adjust their orientation so that, as a group, they capture the maximum possible sunlight with the least overlap between neighbouring leaves.

Leaf type refers to how a leaf's blade is divided into discrete segments, and is judged by the number of segments the petiole bears.

While a leaf's main job is photosynthesis, many leaves are modified for other specialised functions. Leaf tendrils form when a plant's stem is too weak to stand alone, so part or all of a leaf becomes…

Ptyxis is the way an individual leaf is rolled or folded within the bud, before it expands. Reclinate ptyxis is when the upper half of the leaf blade bends down over the lower half, as in loquat (Erio…

Leaf duration is how long a leaf stays on the plant and remains functional, which is largely shaped by adaptation to climate.

Leaf symmetry describes how a leaf is oriented and shaped in cross-section. A dorsiventral leaf is flat, held horizontally, and shows a clearly different upper and lower surface, as in most dicotyledo…

This Evaluation section brings together the chapter's key ideas - plant habit and life span, root structure and modification, stem structure, buds and stem modification, and leaf structure, venation,…

Sample papers and previous-year board questions for this subject.