Biology · Morphology of Flowering Plants · NEET
The three main parts are the leaf base, the petiole and the lamina. The leaf base joins the leaf to the stem, the petiole is the stalk, and the lamina is the flat green blade. NCERT names exactly these three, so any question that lists four or leaves one out is wrong.
The leaf base is the lowest part where the leaf attaches to the stem. The petiole is the stalk above the leaf base that connects the base to the lamina. So order from stem outward is: leaf base, then petiole, then lamina. The petiole holds the blade up to catch light.
A pulvinus is a swollen leaf base. It is found in some leguminous plants (the pea or bean family, Fabaceae). NEET often pairs 'swollen leaf base' with 'pulvinus' and 'leguminous plants', so remember: pulvinus = swollen leaf base of legumes.
Stipules are two small lateral leaf-like structures. They are borne at the leaf base, one on each side. Not every leaf has them, so a leaf 'may bear' stipules. Do not confuse a stipule with a leaflet of a compound leaf.
In monocots (like grasses and wheat), the leaf base expands into a sheath that covers the stem partially or wholly. This is a classic NEET point: 'leaf base expands into a sheath' means monocotyledon.
No. The midrib is not one of the three main parts. It is the middle prominent vein inside the lamina. The lamina contains veins and veinlets, and the largest central vein is the midrib. So the midrib belongs to the lamina, not a fourth part.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
The lamina (also called the leaf blade) is the green expanded flat part. It contains veins and veinlets and does most of the photosynthesis.
No. NCERT says a leaf 'may bear' stipules, so stipules are not always present. Leaves without a petiole are called sessile. The leaf base and lamina, however, are always present.
The petiole holds the leaf blade out to the light. Long, thin, flexible petioles let the blade flutter in the wind, which cools the leaf and brings fresh air to its surface.
Veins give rigidity to the leaf blade and act as channels of transport for water, minerals and food. The middle prominent vein is the midrib.
It is a frequent match-the-term item. NEET links 'swollen leaf base' to 'pulvinus' and to 'leguminous plants'. Knowing this one line prevents an easy negative mark.
