Biology · Plant Kingdom · NEET
A cotyledon is the first leaf (seed leaf) stored inside the seed. It holds food for the baby plant (embryo) until it can make its own food. If the seed has ONE cotyledon, the plant is a monocotyledon (monocot). If it has TWO cotyledons, it is a dicotyledon (dicot). NCERT names wheat and maize as one-cotyledon (monocot) seeds, and gram and pea as two-cotyledon (dicot) seeds. This single feature is the root of the whole classification, so learn it first.
Two quick checks. Roots: dicots usually have a TAP root (one thick main root growing down with side branches), while monocots have a FIBROUS root (many thin roots from the base of the stem). Leaves: dicots show RETICULATE venation (veins form a net), and monocots show PARALLEL venation (veins run side by side, like in grass). NCERT states these directly, so they are safe exam facts.
Flower parts (petals, sepals) come in sets. Monocot flowers are usually TRIMEROUS — parts in multiples of 3 (3, 6, etc.). Dicot flowers are usually TETRAMEROUS or PENTAMEROUS — parts in multiples of 4 or 5. This is a common comparison table point. Remember: monocot = 3s, dicot = 4s or 5s.
They are both inside ANGIOSPERMS (flowering plants with seeds enclosed in a fruit). NCERT clearly says the angiosperms are divided into two classes — the dicotyledons and the monocotyledons. Gymnosperms (naked-seed plants) are NOT split this way. This is a frequent trap: monocot/dicot is an angiosperm-only division.
Generally NO. Most monocot stems and roots lack vascular cambium, so they usually do not undergo secondary growth (they do not add wood to get thick). Dicots have cambium between xylem and phloem, so dicot stems and roots CAN grow thicker over time. That is why big woody trees are mostly dicots or gymnosperms, and grasses (monocots) stay slender.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Monocots: wheat, maize (corn), and grasses (also rice, onion, orchids). Dicots: gram, pea, and mango (also mustard, sunflower). NCERT uses wheat/maize for one cotyledon and gram/pea for two cotyledons.
Yes. The names come from the seed leaf count: 'mono' = one cotyledon, 'di' = two cotyledons. Root type, venation, and flower parts are supporting features that follow from this basic split.
Fibrous roots. NCERT states monocotyledonous plants generally have fibrous roots, while dicotyledonous plants generally have tap roots.
Reticulate (net-like) venation. Monocot leaves have parallel venation. NCERT says reticulate venation is typical of dicots and parallel venation of most monocots.
Dicots. They have vascular cambium, so their stems and roots can grow thicker. Monocots usually lack cambium and do not show secondary growth.
