Biology · Anatomy of Flowering Plants · NEET
| Vascular bundle arrangement | In a ring | Scattered in ground tissue |
| Bundle type (cambium) | Open (cambium present) | Closed (cambium absent) |
| Secondary growth | Present | Normally absent |
| Phloem parenchyma | Present | Absent |
| Hypodermis | Collenchymatous | Sclerenchymatous |
| Bundle sheath | Absent (no sclerenchyma sheath) | Present (sclerenchymatous) |
| Ground tissue | Divided into cortex, endodermis, pericycle, pith | Continuous parenchyma; no distinct cortex or pith |
| Water-containing cavities | Absent | Present within bundles |
In a dicot stem the vascular bundles are OPEN. This means a strip of cambium sits between the xylem and phloem. Because a cambium is present, the dicot stem can undergo secondary growth and become thick and woody. In a monocot stem the bundles are CLOSED (no cambium), so the stem cannot do normal secondary growth. This open-vs-closed point is a very common NEET one-liner.
In a monocot stem there is no cambium ring to organise the bundles, so a large number of small bundles lie spread out through the whole ground tissue instead of forming one neat ring. Each scattered bundle is surrounded by a sclerenchymatous bundle sheath. Note: the peripheral (outer) bundles are generally smaller, and the central ones are larger. This 'scattered' arrangement is the single fastest way to recognise a monocot stem in a diagram.
No. In a monocot stem the phloem parenchyma is ABSENT. The phloem contains only sieve tubes and companion cells. A dicot stem, in contrast, HAS phloem parenchyma. NEET 2020 and NEET 2025 both used this exact fact, so remember: monocot stem = no phloem parenchyma.
The hypodermis of a MONOCOT stem is SCLERENCHYMATOUS (thick-walled, giving mechanical strength). The hypodermis of a DICOT stem is collenchymatous. NEET 2025 tested exactly this: the wrong statement was 'Hypodermis is parenchymatous' for a monocot stem. Do not confuse hypodermis with the sclerenchymatous bundle sheath around each bundle.
A monocot stem has no clear, separate pith. Its ground tissue is not divided into cortex, endodermis and pith; instead it is one large, continuous parenchymatous ground tissue with scattered bundles in it. A dicot stem does show distinct regions: cortex, endodermis (starch sheath), pericycle, pith and medullary rays.
The transverse section of a plant shows the following anatomical features: (a) Large number of scattered vascular bundles surrounded by bundle sheath (b) Large conspicuous parenchymatous ground tissue (c) Vascular bundles conjoint and closed (d) Phloem parenchyma absent. Identify the plant material:
Find the statement that is NOT correct with regard to the structure of monocot stem.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Look at bundle arrangement. A ring of vascular bundles = dicot stem. Bundles scattered all over the ground tissue = monocot stem. This one clue answers most NEET identification questions.
Yes. In both, the bundles are conjoint (xylem and phloem on the same radius, phloem outside xylem). The difference is that dicot bundles are OPEN (cambium present) while monocot bundles are CLOSED (cambium absent).
Only the dicot stem, because its open bundles contain a cambium that forms a full cambial ring. A monocot stem has closed bundles with no cambium, so it normally has no secondary growth.
Water-containing cavities inside the vascular bundles, and a sclerenchymatous bundle sheath around each bundle, are typical monocot-stem features. A monocot stem also has a sclerenchymatous hypodermis, while a dicot stem has a collenchymatous hypodermis.
The dicot stem (like the monocot stem) has ENDARCH xylem, meaning the protoxylem lies toward the centre and metaxylem toward the outside. Exarch xylem is a feature of roots, not stems.
