How to Use This Section
Morphology is a vocabulary chapter. There is nothing to derive and almost nothing to reason out - what is tested is whether you know the exact term and the exact plant that goes with it. A definition without its example is half an answer, and the wrong example turns a right definition into a wrong one.
The 47 questions are organised in three tiers:
- Concept Checks - the definitions the paper quotes word for word.
- Application and Scenarios - a plant part described, and you name it.
- Analytical and Multi-Concept - the pairs and ladders that run across the whole chapter.
Every item is set as a Question with a worked Answer, written the way you would write it in the exam.
Coverage of the chapter-end exercises
| Exercise | Where it is answered |
|---|---|
| 1 - Pinnately against palmately compound leaf | Question 37 |
| 2 - The different types of phyllotaxy, with examples | Question 38 |
| 3(a) - Define aestivation | Question 1 |
| 3(b) - Define placentation | Question 2 |
| 3(c) - Define actinomorphic | Question 3 |
| 3(d) - Define zygomorphic | Question 4 |
| 3(e) - Define superior ovary | Question 5 |
| 3(f) - Define perigynous flower | Question 6 |
| 3(g) - Define epipetalous stamen | Question 7 |
| 4(a) - Racemose against cymose inflorescence | Question 39 |
| 4(b) - Apocarpous against syncarpous ovary | Question 40 |
| 5(i) - Labelled diagram of a gram seed | Question 41 |
| 5(ii) - Labelled diagram of a V.S. of a maize seed | Question 42 |
| 6 - Semi-technical description of a Solanaceae flower, with its floral diagram | Question 43 |
| 7 - The various types of placentation | Question 44 |
| 8 - What a flower is, and the parts of a typical angiosperm flower | Question 45 |
| 9 - Define inflorescence and explain the basis of its types | Question 46 |
| 10 - Floral members in relation to their insertion on the thalamus | Question 47 |
Every chapter-end exercise is worked here, so this section is the one place to check that you have covered the textbook in full.
The Facts These Questions Draw On
Root. Tap (radicle, dicots, mustard), fibrous (base of the stem, monocots, wheat), adventitious (anything but the radicle; grass, Monstera, banyan). Regions from the tip: root cap, meristematic, elongation, maturation with root hairs.
Stem and leaf. Stem from the plumule, with nodes and internodes. Leaf parts: leaf base, petiole, lamina; stipules; sheathing base in monocots; pulvinus in legumes; midrib.
Leaf types. Reticulate dicot, parallel monocot. Simple - incisions do not touch the midrib; compound - they do. Pinnately compound with a rachis (neem); palmately compound from the petiole tip (silk cotton). Bud in the axil of the petiole, never of a leaflet. Phyllotaxy: alternate (china rose, mustard, sunflower), opposite (Calotropis, guava), whorled (Alstonia).
Inflorescence. Racemose - axis grows on, flowers acropetal. Cymose - axis ends in a flower, flowers basipetal.
Flower. Four whorls on the thalamus; calyx and corolla accessory, androecium and gynoecium reproductive; perianth in lily. Actinomorphic (mustard, datura, chilli), zygomorphic (pea, gulmohur, bean, Cassia), asymmetric (canna). Hypogynous / superior (mustard, china rose, brinjal), perigynous / half inferior (plum, rose, peach), epigynous / inferior (guava, cucumber, ray florets of sunflower).
Aestivation. Valvate (Calotropis), twisted (china rose, lady's finger, cotton), imbricate (Cassia, gulmohur), vexillary (pea, bean; standard, wings, keel).
Androecium and gynoecium. Epipetalous (brinjal), epiphyllous (lily); monoadelphous (china rose), diadelphous (pea), polyadelphous (citrus). Carpel = stigma, style, ovary; apocarpous (lotus, rose), syncarpous (mustard, tomato).
Placentation. Marginal (pea), axile (china rose, tomato, lemon), parietal (mustard, Argemone, false septum), free central (Dianthus, primrose, no septa), basal (sunflower, marigold, one ovule).
Fruit and seed. Fruit = ripened ovary; parthenocarpic without fertilisation; epicarp, mesocarp, endocarp. Drupe - mango (fleshy mesocarp), coconut (fibrous mesocarp). Dicot seed - testa, tegmen, hilum, micropyle, two cotyledons; castor endospermic, bean, gram, pea non-endospermous. Monocot seed - membranous coat fused to fruit wall, bulky endosperm, aleurone layer, scutellum, coleoptile, coleorhiza; orchids non-endospermic.
Tier 1 - Concept Checks
Question 1
Q. Define aestivation.
Answer. The mode of arrangement of sepals or petals in the floral bud with respect to the other members of the same whorl. This is one of the chapter-end exercises.
Question 2
Q. Define placentation.
Answer. The arrangement of ovules within the ovary. This is one of the chapter-end exercises.
Question 3
Q. Define actinomorphic.
Answer. A flower that can be divided into two equal radial halves in any radial plane passing through the centre. Mustard, datura and chilli. This is one of the chapter-end exercises.
Question 4
Q. Define zygomorphic.
Answer. A flower that can be divided into two similar halves only in one particular vertical plane. Pea, gulmohur, bean and Cassia. This is one of the chapter-end exercises.
Question 5
Q. Define a superior ovary.
Answer. The ovary of a hypogynous flower, where the gynoecium occupies the highest position and all the other floral parts sit below it. Mustard, china rose, brinjal. This is one of the chapter-end exercises.
Question 6
Q. Define a perigynous flower.
Answer. One in which the gynoecium is in the centre and the other parts sit on the rim of the thalamus at almost the same level, so the ovary is half inferior. Plum, rose, peach. This is one of the chapter-end exercises.
Question 7
Q. Define an epipetalous stamen.
Answer. A stamen that is attached to the petals, as in brinjal. This is one of the chapter-end exercises.
Question 8
Q. Define phyllotaxy and venation.
Answer. Phyllotaxy is the pattern of arrangement of leaves on the stem or branch. Venation is the arrangement of veins and veinlets in the lamina of a leaf. One is about the stem, the other about the blade.
Question 9
Q. Define inflorescence.
Answer. The arrangement of flowers on the floral axis. This is one of the chapter-end exercises.
Question 10
Q. What is a parthenocarpic fruit?
Answer. A fruit formed without fertilisation of the ovary.
Question 11
Q. Name the three parts of a typical leaf and the three parts of a carpel.
Answer. Leaf - leaf base, petiole, lamina. Carpel - stigma, style, ovary.
Question 12
Q. What is a pulvinus and what is a staminode?
Answer. A pulvinus is a swollen leaf base, found in some leguminous plants. A staminode is a sterile stamen.
Question 13
Q. What are the testa, tegmen, hilum and micropyle?
Answer. Testa - the outer layer of the seed coat. Tegmen - the inner layer. Hilum - the scar where the seed was attached to the fruit. Micropyle - the small pore just above the hilum.
Question 14
Q. What are the coleoptile, coleorhiza and scutellum?
Answer. In a monocot seed the coleoptile is the sheath over the plumule, the coleorhiza is the sheath over the radicle, and the scutellum is the single large shield-shaped cotyledon.
Question 15
Q. Name the four regions of a root tip in order from the apex.
Answer. Root cap, region of meristematic activity, region of elongation, region of maturation.
Question 16
Q. What do gamosepalous, polysepalous, gamopetalous and polypetalous mean?
Answer. Gamo- means united and poly- means free. So the sepals are united in a gamosepalous calyx and free in a polysepalous one, and the petals are united in a gamopetalous corolla and free in a polypetalous one.
Tier 2 - Application and Scenarios
Question 17
Q. A leaf shows a network of veinlets. What can you say about the plant?
Answer. The venation is reticulate, so the plant is generally a dicotyledon. Parallel venation would have pointed to a monocotyledon instead.
Question 18
Q. A cluster of blades comes off a single stalk, and there is a bud at the base of that stalk but none at the base of any blade. What are you holding?
Answer. One compound leaf, and the blades are its leaflets. A bud sits in the axil of a petiole in both simple and compound leaves, but never in the axil of a leaflet, so the single bud at the base tells you this is one leaf, not several.
Question 19
Q. A plant bears three leaves at every node. Name the phyllotaxy and the plant given for it.
Answer. Whorled phyllotaxy - more than two leaves at a node forming a whorl. Alstonia.
Question 20
Q. In an inflorescence the lowest flowers have already set fruit while new buds keep appearing at the tip. Name the type and the order of opening.
Answer. Racemose, opening in acropetal succession. The main axis is still growing, which is what allows new flowers to keep coming.
Question 21
Q. A flower can be cut into matching halves along one vertical plane only. Name the symmetry and give two examples.
Answer. Zygomorphic. Pea and gulmohur - and Cassia and bean fit as well.
Question 22
Q. The sepals, petals and stamens of a flower all arise from above the ovary. Name the flower type, the ovary and two plants.
Answer. The flower is epigynous and the ovary is inferior, because the thalamus has grown up around the ovary and fused with it. Guava and cucumber.
Question 23
Q. In a floral bud, each petal overlaps the next one in the same direction all the way round. Name the aestivation and give an example.
Answer. Twisted. The regular one-way overlap is the test. China rose.
Question 24
Q. A flower has five stamens fused into a single bundle. Name the condition and the plant.
Answer. Monoadelphous, as in china rose. Two bundles would be diadelphous and more than two polyadelphous.
Question 25
Q. An ovary is one-chambered, its ovules sit on the inner wall, and a partition has divided it in two. Name the placentation and the plants.
Answer. Parietal. The partition is the false septum, which belongs to no other placentation. Mustard and Argemone.
Question 26
Q. A single-seeded fruit has a thin skin, a fibrous middle layer and a hard shell. Name the fruit type and the plant.
Answer. A drupe, and the fibrous mesocarp identifies it as coconut. In mango, the other drupe, the mesocarp is fleshy and edible.
Question 27
Q. A seed has a bulky food store, a single shield-shaped cotyledon and two sheaths on a short axis. Which class does the plant belong to, and name the three structures.
Answer. A monocotyledon. The cotyledon is the scutellum, and the two sheaths are the coleoptile over the plumule and the coleorhiza over the radicle.
Question 28
Q. A flower has a green star-shaped structure still attached at the top of the ripe fruit. Which family is it, and what is the structure?
Answer. Solanaceae, and the structure is the persistent calyx - the five united sepals stay on after the flower becomes a fruit. Tomato and brinjal both show it.
Tier 3 - Analytical and Multi-Concept
Question 29
Q. Four terms in this chapter describe an arrangement. Name each one and say what is being arranged.
Answer.
| Term | What is arranged |
|---|---|
| Phyllotaxy | Leaves on the stem or branch |
| Venation | Veins and veinlets in the lamina |
| Inflorescence | Flowers on the floral axis |
| Aestivation | Sepals or petals in the floral bud, against others of the same whorl |
| Placentation | Ovules within the ovary |
Five, in fact. Questions in this chapter very often come down to knowing which of these words is being asked for.
Question 30
Q. Group the flowers of this chapter by their ovary, and give the flower type for each.
Answer.
| Ovary | Flower type | Examples |
|---|---|---|
| Superior | Hypogynous | Mustard, china rose, brinjal |
| Half inferior | Perigynous | Plum, rose, peach |
| Inferior | Epigynous | Guava, cucumber, ray florets of sunflower |
The naming follows one simple rule: the flower type is named for where the other parts sit relative to the ovary, and the ovary is then named for the opposite position.
Question 31
Q. China rose appears three times in this chapter, in three different topics. Where, and what is it an example of each time?
Answer. Phyllotaxy - alternate. Aestivation - twisted. Androecium - monoadelphous. It is also a hypogynous flower with a superior ovary and axile placentation, so it turns up five times if you count those. That is why it makes such a good examination example - one plant, several answers, and you have to read which topic is being asked about.
Question 32
Q. Mustard runs through this chapter as well. List every place it appears.
Answer. Tap root system. Alternate phyllotaxy. Actinomorphic flower. Hypogynous flower with a superior ovary. Syncarpous gynoecium. Parietal placentation with a false septum. Variation in filament length. And its floral formula, K2+2 C4 A2+4 G(2), is the one worked through in the chapter.
Question 33
Q. Which structures in this chapter are named after what they cover or protect?
Answer.
- Root cap - covers and protects the tender apex of the root.
- Sepals - protect the flower in the bud stage.
- Coleoptile - sheathes the plumule.
- Coleorhiza - sheathes the radicle.
- Seed coat, of testa and tegmen - covers the embryo.
- Pericarp - the wall of the fruit, covering the seeds.
Question 34
Q. Trace what each part of a flower becomes after fertilisation.
Answer. The ovules develop into seeds and the ovary matures into a fruit. That single line links the flower section to the fruit and seed section, and it is why a fruit is defined as a ripened ovary and a seed as a fertilised ovule.
Question 35
Q. Two structures in this chapter are called tendrils and two are called spines or thorns, in different organs. Sort them out.
Answer. A stem tendril comes from an axillary bud, as in the gourds and the grapevine; a leaf tendril is made of leaflets or the leaf tip, as in pea and Gloriosa. A thorn is a modified branch, as in Citrus; a spine is a modified leaf, as in Opuntia. Same shape, different origins - and the origin is always what the question is really asking. These belong to the bonus section on modifications rather than to the current chapter.
Question 36
Q. Build the shortest set of questions that would let you place any leaf you are handed.
Answer.
- Do the veinlets form a network or run parallel? Network means reticulate and probably a dicot; parallel means a monocot.
- Do the incisions reach the midrib? No means simple; yes means compound.
- If compound, where do the leaflets attach? On a rachis means pinnately compound (neem); at the tip of the petiole means palmately compound (silk cotton).
- How many leaves at a node? One is alternate, two is opposite, more than two is whorled.
Four questions, and every leaf in the chapter is placed.
The Chapter-End Exercises
These are the textbook's own exercises, worked in full. Every one of them is mapped in the coverage table at the top of this section.
Question 37
Q. How is a pinnately compound leaf different from a palmately compound leaf?
Answer.
| Pinnately compound | Palmately compound | |
|---|---|---|
| Where the leaflets attach | On a common axis, the rachis, which represents the midrib of the leaf | At a common point, the tip of the petiole |
| Rachis | Present | Absent |
| Example | Neem | Silk cotton |
Both are compound, so in both the incisions of the lamina reach the midrib and the bud sits in the axil of the petiole, never in the axil of a leaflet. This is one of the chapter-end exercises.
Question 38
Q. Explain with suitable examples the different types of phyllotaxy.
Answer. Phyllotaxy is the pattern of arrangement of leaves on the stem or branch, and it is of three types.
- Alternate. A single leaf arises at each node in alternate manner. China rose, mustard, sunflower.
- Opposite. A pair of leaves arises at each node and the two lie opposite each other. Calotropis, guava.
- Whorled. More than two leaves arise at a node and form a whorl. Alstonia.
The count of leaves at one node is the whole test - one, two, or more than two. This is one of the chapter-end exercises.
Question 39
Q. Differentiate between racemose and cymose inflorescence.
Answer.
| Racemose | Cymose | |
|---|---|---|
| Main axis | Continues to grow | Terminates in a flower, so growth is limited |
| Position of the flowers | Borne laterally on the growing axis | Borne on an axis that has already ended in a flower |
| Order of opening | Acropetal | Basipetal |
| Oldest flower | At the base | At the top |
The single question that decides it is whether the apex of the main axis goes on growing or turns into a flower. This is one of the chapter-end exercises.
Question 40
Q. Differentiate between an apocarpous and a syncarpous ovary.
Answer.
| Apocarpous | Syncarpous | |
|---|---|---|
| Number of carpels | More than one | More than one |
| State of the carpels | Free from one another | Fused together |
| Examples | Lotus, rose | Mustard, tomato |
Both words describe a gynoecium of more than one carpel; only the fusion separates them. This is one of the chapter-end exercises.
Question 41
Q. Draw a labelled diagram of a gram seed.
Answer. Draw the seed in section and label it, working from the outside in.
- Seed coat, in its two layers - the outer testa and the inner tegmen.
- Hilum - the scar where the seed was attached to the fruit.
- Micropyle - the small pore just above the hilum.
- Cotyledons - two, fleshy and full of reserve food.
- Embryonal axis, carrying the radicle at one end and the plumule at the other.
Gram is non-endospermous, so no endosperm is shown in the diagram. The marks here sit on the labels, not on the drawing. This is one of the chapter-end exercises.
Question 42
Q. Draw a labelled diagram of a vertical section of a maize seed.
Answer. Draw the grain in vertical section and label it.
- Seed coat and fruit wall - membranous and fused together.
- Endosperm - bulky, and it stores the food.
- Aleurone layer - the proteinous layer separating the endosperm from the embryo.
- Scutellum - the single large shield-shaped cotyledon.
- Plumule, enclosed by the coleoptile.
- Radicle, enclosed by the coleorhiza.
The embryo is small and set in a groove at one end of the endosperm. This is one of the chapter-end exercises.
Question 43
Q. Take one flower of the family Solanaceae and write its semi-technical description. Also describe its floral diagram.
Answer. Take Solanum nigrum, the makoi plant.
Habit. A herb.
Vegetative characters
- Stem - herbaceous, rarely woody, aerial, erect, cylindrical, branched, solid or hollow, hairy or glabrous. In potato, Solanum tuberosum, the stem is underground.
- Leaves - alternate, simple, rarely pinnately compound, exstipulate, with reticulate venation.
Floral characters
- Inflorescence - solitary, axillary or cymose.
- Flower - bisexual, actinomorphic.
- Calyx - sepals five, united, persistent, valvate aestivation.
- Corolla - petals five, united, valvate aestivation.
- Androecium - stamens five, epipetalous.
- Gynoecium - bicarpellary, obliquely placed, syncarpous; ovary superior, bilocular, with a swollen placenta bearing many ovules and axile placentation.
- Fruit - a berry or capsule.
- Seeds - many, endospermous.
Floral formula. Written in plain text it is K(5) C(5) A5 G(2). The brackets mean united, so the sepals are united and the petals are united; the A is joined to the C by a line because the stamens are epipetalous; and the line under the G marks the superior ovary. The flower also carries a star-shaped sign for actinomorphic symmetry and a sign combining the male and female symbols for a bisexual flower, both written at the front.
Floral diagram. Put a dot at the top for the mother axis. Then draw four whorls from the outside in - five united sepals, five united petals, five stamens drawn against the corolla to show the adhesion, and at the centre the two obliquely placed fused carpels with a bilocular ovary showing axile placentation.
This is one of the chapter-end exercises.
Question 44
Q. Describe the various types of placentation found in flowering plants.
Answer. Placentation is the arrangement of ovules within the ovary, and there are five types.
- Marginal. The placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge in two rows. Pea.
- Axile. The placenta is axial and the ovules are attached to it in a multilocular ovary. China rose, tomato, lemon.
- Parietal. The ovules develop on the inner wall of the ovary or on its peripheral part. The ovary is one-chambered but becomes two-chambered by the formation of a false septum. Mustard, Argemone.
- Free central. The ovules are borne on the central axis and the septa are absent. Dianthus, primrose.
- Basal. The placenta develops at the base of the ovary and a single ovule is attached to it. Sunflower, marigold.
This is one of the chapter-end exercises.
Question 45
Q. What is a flower? Describe the parts of a typical angiosperm flower.
Answer. The flower is the reproductive unit in the angiosperms, and it is meant for sexual reproduction. It is a modified shoot - the shoot apical meristem changes into a floral meristem, the internodes stop elongating and the axis becomes condensed, so the appendages made at successive nodes come to sit as whorls.
A typical flower has four different kinds of whorls arranged successively on the thalamus or receptacle, which is the swollen end of the pedicel.
- Calyx - the outermost whorl, made of sepals. They are generally green and leaf like, and they protect the flower in the bud stage. The calyx is gamosepalous when the sepals are united and polysepalous when they are free.
- Corolla - made of petals, usually brightly coloured to attract insects for pollination. It is gamopetalous or polypetalous, and its shape may be tubular, bell-shaped, funnel-shaped or wheel-shaped.
- Androecium - made of stamens, the male reproductive organ. Each stamen has a filament and a usually bilobed anther with two pollen-sacs in each lobe, where the pollen grains are produced.
- Gynoecium - the female reproductive part, made of one or more carpels. A carpel has a stigma, a style and an ovary, and the ovary bears the ovules on a flattened cushion-like placenta.
Calyx and corolla are the accessory organs; androecium and gynoecium are the reproductive organs. Where calyx and corolla cannot be told apart, as in lily, the two together are the perianth. After fertilisation the ovules become seeds and the ovary becomes the fruit.
This is one of the chapter-end exercises.
Question 46
Q. Define the term inflorescence and explain the basis for the different types of inflorescence in flowering plants.
Answer. Inflorescence is the arrangement of flowers on the floral axis.
The basis for the two major types is whether the apex of the main axis develops into a flower or goes on growing.
- If the apex continues to grow, the type is racemose. The flowers are borne laterally in acropetal succession, so the oldest flowers are at the base and the youngest near the tip.
- If the apex terminates in a flower, the axis is limited in growth and the type is cymose. The flowers are borne in basipetal order, so the oldest flower is at the top.
A shoot tip that itself turns into a flower gives a solitary flower. This is one of the chapter-end exercises.
Question 47
Q. Describe the arrangement of floral members in relation to their insertion on the thalamus.
Answer. The arrangement depends on where the calyx, corolla and androecium are inserted on the thalamus in relation to the ovary, and there are three cases.
| Type | The arrangement | Ovary | Examples |
|---|---|---|---|
| Hypogynous | The gynoecium occupies the highest position and the other parts are inserted below it | Superior | Mustard, china rose, brinjal |
| Perigynous | The gynoecium is in the centre and the other parts sit on the rim of the thalamus at almost the same level | Half inferior | Plum, rose, peach |
| Epigynous | The thalamus grows upward, encloses the ovary completely and fuses with it, and the other parts arise above the ovary | Inferior | Guava, cucumber, ray florets of sunflower |
The flower takes its name from where the other floral members sit, and the ovary then takes the opposite name. This is one of the chapter-end exercises.