Description of Some Important Families

BiologyMorphology of Flowering PlantsFor NEET aspirants

A semi-technical description presents a flowering plant in a fixed order and ends with a floral diagram and a floral formula. This page explains the floral formula symbols, how to read a floral diagram and the mustard formula. It then describes the family Solanaceae, the potato family, and its economic importance, as given in NCERT Class 11. NEET often asks floral formula symbols and the characters of the family Solanaceae in statement and match-the-list questions.

On this page1Description order2Floral formula3Floral diagram4Solanaceae5Economic importance6Exam essentials7Practice

Key Points at a Glance

★ Must learn Description order: habit, vegetative characters (roots, stem, leaves), floral characters (inflorescence, flower parts), then floral diagram and floral formula.
Symbols: Br bracteate, K calyx, C corolla, P perianth, A androecium, G gynoecium.
★ Must learn $\underline{G}$ = superior ovary; $\overline{G}$ = inferior ovary.
$\oplus$ actinomorphic, $%$ zygomorphic; ♂ male, ♀ female, ⚥ bisexual.
★ Must learn Fusion: figure enclosed in a bracket. Adhesion: a line drawn above the symbols.
Floral diagram: the mother axis is a dot at the top; calyx outermost, gynoecium in the centre.
Mustard (Brassicaceae): $\oplus$ ⚥ $K_{2 + 2} C_{4} A_{2 + 4} \underline{G}_{(2)}$ .
★ Must learn Solanaceae: $\oplus$ ⚥ $K_{(5)} \overline{C_{(5)} A_{5}} \underline{G}_{(2)}$ ; bisexual, actinomorphic, epipetalous stamens, superior bilocular ovary with axile placentation.
Solanaceae fruits: berry or capsule; seeds many, endospermous.
★ Must learn Uses: food (tomato, brinjal, potato), spice (chilli), medicine (belladonna, ashwagandha), fumigatory (tobacco), ornamental (petunia).

1. Semi-technical Description of a Flowering Plant

Various morphological features are used to describe a flowering plant.
The description must be brief, in simple and scientific language, and in a proper sequence.
★ Exam imp The plant is described in this order:

Habit of the plant (herb, shrub or tree).
Vegetative characters: roots, stem and leaves.
Floral characters: inflorescence and flower parts.
A floral diagram and a floral formula.

Memory Trick

Description order: "Healthy Vegetables, Fresh Flowers" = Habit, Vegetative characters, Floral characters, Floral diagram and formula.

Key idea

A semi-technical description runs from habit to vegetative to floral characters and ends with a floral diagram and formula.

2. The Floral Formula

The floral formula represents the flower with symbols.

Symbol	Meaning
Br	Bracteate
K	Calyx
C	Corolla
P	Perianth
A	Androecium
G	Gynoecium
$\underline{G}$ (line below G)	Superior ovary
$\overline{G}$ (line above G)	Inferior ovary
♂	Male
♀	Female
⚥	Bisexual
$\oplus$	Actinomorphic
$%$	Zygomorphic

★ Exam imp Fusion is shown by enclosing the figure within a bracket: $K_{(5)}$ means five united sepals.
Adhesion is shown by a line drawn above the symbols of the floral parts.
The floral formula shows cohesion (union of members of the same whorl) and adhesion (union of members of different whorls).
It shows these both within parts of whorls and between whorls.

★ Very important A line below G means a superior ovary; a line above G means an inferior ovary. A bracket means fusion of members of the same whorl; a line over two whorls means adhesion between them.

Memory Trick

The line marks where the other floral parts sit. In a hypogynous flower they sit below the ovary, so the line goes below G (superior ovary). In an epigynous flower they arise above the ovary, so the line goes above G (inferior ovary).

Memory Trick

Symbol letters: K for calyx (from the Greek kalyx), Corolla, Androecium, Gynoecium, Perianth, Bract. $\oplus$ looks like a wheel = radial (actinomorphic); $%$ has one dividing stroke = one plane (zygomorphic).

Quick Recall: tap to check

What does Br stand for in a floral formula?

Bracteate.

How is fusion of members of a whorl shown?

By enclosing the number in a bracket.

What does the symbol

%

show?

A zygomorphic flower.

Key idea

Brackets show fusion within a whorl, a line above shows adhesion between whorls, and the line under or over G shows the ovary position.

3. The Floral Diagram

A floral diagram gives the number of parts of a flower, their arrangement and their relation to one another.
★ Exam imp The position of the mother axis with respect to the flower is shown by a dot on the top of the floral diagram.
Calyx, corolla, androecium and gynoecium are drawn in successive whorls.
The calyx is the outermost whorl; the gynoecium is in the centre.
The floral diagram and formula below represent the mustard plant (family Brassicaceae).

Test yourself: hide labels

Figure 1: Floral diagram with floral formula of mustard (family Brassicaceae). The dot at the top marks the mother axis; the whorls run from the calyx outside to the gynoecium in the centre.

Mustard floral formula: $\oplus$ ⚥ $K_{2 + 2} C_{4} A_{2 + 4} \underline{G}_{(2)}$ .

Part of the formula	Reading
$\oplus$ ⚥	Actinomorphic and bisexual flower
$K_{2 + 2}$	Four sepals in two whorls of two, free
$C_{4}$	Four free petals
$A_{2 + 4}$	Six free stamens in two whorls: two outer and four inner
$\underline{G}_{(2)}$	Two fused carpels (syncarpous) with a superior ovary

NEET Focus

In $K_{2 + 2}$ and $A_{2 + 4}$ , the plus sign separates two whorls; the absence of brackets means the members are free.
In $\underline{G}_{(2)}$ , the bracket shows the two carpels are fused and the line below G shows a superior ovary.

Tips and Tricks

To read any floral formula, go left to right: symmetry, sex, then K, C, A, G. For each whorl ask three things: how many members (number), are they joined (bracket), and are they joined to another whorl (line above).

Key idea

The floral diagram shows number, arrangement and relations of floral parts, with the mother axis as a dot at the top.

4. Family Solanaceae

Solanaceae is a large family, commonly called the potato family.
It is widely distributed in the tropics, subtropics and even temperate zones.

4.1 Vegetative characters

Character	Description
Habit	Mostly herbs and shrubs; rarely small trees
Stem	Herbaceous, rarely woody; aerial; erect, cylindrical, branched, solid or hollow, hairy or glabrous (smooth); underground stem in potato (Solanum tuberosum)
Leaves	Alternate, simple, rarely pinnately compound, exstipulate (without stipules); venation reticulate

Test yourself: hide labels

Figure 2: Solanum nigrum (makoi): (a) a flowering twig and (b) a flower.

4.2 Floral characters

Character	Description
Inflorescence	Solitary, axillary or cymose, as in Solanum
Flower	Bisexual, actinomorphic
Calyx	Sepals five, united, persistent (stays on the fruit), valvate aestivation
Corolla	Petals five, united; valvate aestivation
Androecium	Stamens five, epipetalous
Gynoecium	Bicarpellary, obliquely placed, syncarpous; ovary superior, bilocular; placenta swollen with many ovules; axile placentation
Fruits	Berry or capsule
Seeds	Many, endospermous

Solanaceae floral formula: $\oplus$ ⚥ $K_{(5)} \overline{C_{(5)} A_{5}} \underline{G}_{(2)}$ . The line above C and A shows that the stamens adhere to the petals (epipetalous).

Test yourself: hide labels

Figure 3: Solanum nigrum: (c) L.S. of the flower, (d) stamens and (e) carpel. The stamens are joined to the corolla and the ovary is superior.

Test yourself: hide labels

Figure 4: (f) Floral diagram of Solanum nigrum, with its floral formula: five united sepals, five united petals, five epipetalous stamens and a bilocular ovary with an oblique septum.

★ Very important Solanaceae: K(5) C(5) A5 G(2), with epipetalous stamens, a superior bilocular ovary, an obliquely placed septum and axile placentation on a swollen placenta.

Memory Trick

5-5-5-2 for Solanaceae: five sepals (united), five petals (united), five stamens (on the petals), two carpels (fused, superior). Both calyx and corolla are valvate.

4.3 Economic importance

Use	Plants
Food	Tomato, brinjal, potato
Spice	Chilli
Medicine	Belladonna, ashwagandha
Fumigatory	Tobacco
Ornamental	Petunia

Memory Trick

Uses in order: "Fresh Spicy Medicine Fumes Out" = Food (tomato, brinjal, potato), Spice (chilli), Medicine (belladonna, ashwagandha), Fumigatory (tobacco), Ornamental (petunia).

Key idea

Solanaceae: potato family; actinomorphic bisexual flowers, epipetalous stamens, superior bilocular ovary; food, spice, medicine, tobacco and petunia.

5. Why Floral Characters Matter

Flowering plants vary enormously in shape, size, structure, mode of nutrition, life span, habit and habitat.
They have well-developed root and shoot systems.
★ Exam imp Floral characteristics form the basis of classification and identification of flowering plants.
This is shown through semi-technical descriptions of families.
A flowering plant is described in a definite sequence using scientific terms.
Floral features are summarised as floral diagrams and floral formulae.

Key idea

Families are identified mainly by floral characters, written in a fixed order and summarised as a floral diagram and formula.

6. Exam Essentials

Pairs to Match

List I	List II
K	Calyx
P	Perianth
Br	Bracteate
$\oplus$	Actinomorphic
$%$	Zygomorphic
⚥	Bisexual
$\underline{G}$	Superior ovary
$\overline{G}$	Inferior ovary
Bracket around a number	Fusion
Line above the symbols	Adhesion
Dot at the top of a floral diagram	Mother axis
Mustard	Brassicaceae
Potato family	Solanaceae
Tobacco	Fumigatory
Belladonna, ashwagandha	Medicine

Numbers to Remember

Mustard: 4 sepals (2 + 2), 4 petals, 6 stamens (2 + 4), 2 fused carpels.
Solanaceae: 5 united sepals, 5 united petals, 5 epipetalous stamens, 2 fused carpels.
Solanaceae ovary: bilocular (2 chambers), with many ovules; seeds many.

Examples to Remember

Use (Solanaceae)	Examples
Food	Tomato, brinjal, potato
Spice	Chilli
Medicine	Belladonna, ashwagandha
Fumigatory	Tobacco
Ornamental	Petunia
Underground stem	Potato (Solanum tuberosum)
Floral diagram described	Solanum nigrum (makoi)

Exceptions

Solanaceae plants are mostly herbs and shrubs, rarely small trees.
The stem is herbaceous, rarely woody; potato has an underground stem.
Leaves are simple, rarely pinnately compound, and have no stipules (exstipulate).
The calyx is persistent: it does not fall off after fertilisation.
The septum of the ovary is obliquely placed, not straight.

Quick Recall: tap to check

What does a line above the symbols C and A in a floral formula show?

Adhesion: the stamens are attached to the petals (epipetalous).

Write the floral formula of mustard.

\oplus

⚥

K_{2 + 2} C_{4} A_{2 + 4} \underline{G}_{(2)}

, with the line below G showing a superior ovary.

What does the dot at the top of a floral diagram represent?

The position of the mother axis.

Name the type of placentation in Solanaceae.

Axile, on a swollen placenta with many ovules.

7. Quick Revision

Semi-technical description: brief, scientific, in a proper sequence.
Order: habit, vegetative characters, floral characters, floral diagram and formula.
K calyx, C corolla, P perianth, A androecium, G gynoecium, Br bracteate.
Line below G: superior ovary; line above G: inferior ovary.
$\oplus$ actinomorphic, $%$ zygomorphic; ♂ male, ♀ female, ⚥ bisexual.
Bracket: fusion; line above symbols: adhesion.
Floral formula shows cohesion and adhesion within and between whorls.
Floral diagram: number, arrangement and relation of parts; mother axis as a dot on top.
Calyx outermost, gynoecium in the centre.
Mustard (Brassicaceae): $\oplus$ ⚥ $K_{2 + 2} C_{4} A_{2 + 4} \underline{G}_{(2)}$ .
Solanaceae: potato family; tropics, subtropics, temperate zones.
Herbs or shrubs; leaves alternate, simple, exstipulate, reticulate.
Flowers bisexual, actinomorphic; K(5) persistent valvate; C(5) valvate; A5 epipetalous.
G(2) obliquely placed, superior, bilocular, axile on a swollen placenta; berry or capsule; many endospermous seeds.
Food, spice, medicine, fumigatory and ornamental plants.

8. Solved Examples

Solved Example 1

Match List I with List II.
List I: A.

\oplus

; B.

%

; C.

\underline{G}

; D. ⚥
List II: I. Superior ovary; II. Bisexual; III. Actinomorphic; IV. Zygomorphic
Choose the correct answer.
(A) A-III, B-IV, C-II, D-I
(B) A-IV, B-III, C-I, D-II
(C) A-III, B-IV, C-I, D-II
(D) A-III, B-I, C-IV, D-II

Solution:

Answer: (C). $\oplus$ is actinomorphic, $%$ zygomorphic, a line below G a superior ovary, and ⚥ a bisexual flower.

Solved Example 2

Arrange the parts of a semi-technical description in the correct sequence.
A. Floral diagram and floral formula; B. Habit; C. Floral characters; D. Vegetative characters
Choose the correct order.
(A) B, D, C, A
(B) D, B, C, A
(C) B, C, D, A
(D) A, B, D, C

Solution:

Answer: (A). Habit first, then roots, stem and leaves, then inflorescence and flower parts, and finally the floral diagram and formula.

Solved Example 3

Read the statements about Solanaceae.
A. The stamens are epipetalous.
B. The ovary is inferior.
C. The calyx is persistent.
D. The leaves have stipules.
E. The placentation is axile.
Choose the correct answer.
(A) A, B and C only
(B) B, D and E only
(C) C, D and E only
(D) A, C and E only

Solution:

Answer: (D). B is false: the ovary is superior. D is false: the leaves are exstipulate. A, C and E are true.

Solved Example 4

Match List I with List II.
List I: A. Tobacco; B. Petunia; C. Chilli; D. Belladonna
List II: I. Spice; II. Medicine; III. Fumigatory; IV. Ornamental
Choose the correct answer.
(A) A-III, B-IV, C-II, D-I
(B) A-III, B-IV, C-I, D-II
(C) A-IV, B-III, C-I, D-II
(D) A-II, B-IV, C-I, D-III

Solution:

Answer: (B). Tobacco is fumigatory, petunia ornamental, chilli a spice and belladonna a medicine.

Solved Example 5

Which of the following is NOT a character of the family Solanaceae?
(A) Bicarpellary, syncarpous gynoecium
(B) Five united petals with valvate aestivation
(C) Six stamens in two whorls
(D) Fruit a berry or capsule

Solution:

Answer: (C). Six stamens in two whorls ( $A_{2 + 4}$ ) belong to mustard. Solanaceae has five epipetalous stamens.

Solved Example 6

Statement I: In the floral formula of Solanaceae, a line is drawn above C and A.
Statement II: The stamens of Solanaceae are attached to the petals.
Choose the correct answer.
(A) Both Statement I and Statement II are correct
(B) Both Statement I and Statement II are incorrect
(C) Statement I is correct but Statement II is incorrect
(D) Statement I is incorrect but Statement II is correct

Solution:

Answer: (A). The line shows adhesion of the stamens to the petals, which is the epipetalous condition.

9. Practice Questions

Practice Questions

Take one flower of the family Solanaceae and write its semi-technical description. Also draw its floral diagram.Answer: Flower bisexual, actinomorphic. Calyx: five united sepals, persistent, valvate. Corolla: five united petals, valvate. Androecium: five epipetalous stamens. Gynoecium: bicarpellary, obliquely placed, syncarpous; ovary superior, bilocular, axile on a swollen placenta with many ovules. Formula: $\oplus$ ⚥ $K_{(5)} \overline{C_{(5)} A_{5}} \underline{G}_{(2)}$ . The floral diagram is shown in Figure 4.
In a floral formula, a superior ovary is shown by
(a) a bracket around G
(b) a line above G
(c) a line below G
(d) the symbol PAnswer: (c) A line below G.
Match List I with List II. List I: A. Habit; B. Leaves; C. Inflorescence; D. Seeds (Solanaceae). List II: I. Solitary, axillary or cymose; II. Many, endospermous; III. Mostly herbs and shrubs; IV. Alternate, simple, exstipulate.
(1) A-III, B-IV, C-I, D-II
(2) A-IV, B-III, C-I, D-II
(3) A-III, B-I, C-IV, D-II
(4) A-III, B-IV, C-II, D-IAnswer: (1). Habit: mostly herbs and shrubs; leaves: alternate, simple, exstipulate; inflorescence: solitary, axillary or cymose; seeds: many, endospermous.
Read the statements. A. The mother axis is shown by a dot at the top of the floral diagram. B. Gynoecium is drawn as the outermost whorl. C. Fusion is shown by a bracket. D. The floral formula shows cohesion and adhesion.
(1) A, C and D only
(2) A and B only
(3) B, C and D only
(4) A, B and D onlyAnswer: (1). B is false: the calyx is outermost; the gynoecium is in the centre.
Which plant of the family Solanaceae is NOT a source of food?
(a) Tomato
(b) Brinjal
(c) Potato
(d) PetuniaAnswer: (d) Petunia, which is ornamental.
Statement I: Mustard belongs to Brassicaceae. Statement II: The floral formula of mustard shows six stamens in two whorls.
(1) Both correct
(2) Both incorrect
(3) I correct, II incorrect
(4) I incorrect, II correctAnswer: (1). $A_{2 + 4}$ means two outer and four inner stamens.
Why are floral characters important in the classification of flowering plants?Answer: Floral characteristics form the basis of classification and identification of flowering plants; families are described semi-technically and summarised as floral diagrams and formulae.

Common Mistakes to Avoid

Watch out

Reading a line below G as an inferior ovary. A line below G means a superior ovary.
Confusing the bracket and the line: a bracket shows fusion; a line above the symbols shows adhesion.
Drawing the gynoecium as the outer whorl. The calyx is outermost; the gynoecium is central.
Writing that Solanaceae leaves have stipules. They are exstipulate.
Calling the Solanaceae ovary inferior or unilocular. It is superior and bilocular.
Writing "obligately placed" for the carpels. The correct term is obliquely placed.
Giving mustard five stamens. Mustard has six stamens ( $A_{2 + 4}$ ); Solanaceae has five.
Listing tobacco as a medicine. Tobacco is fumigatory; belladonna and ashwagandha are medicinal.

Frequently Asked Questions

What is a semi-technical description of a flowering plant?

It is a brief description in simple, scientific language and a fixed sequence. It begins with the habit and then gives the vegetative characters: roots, stem and leaves. Next come the floral characters, the inflorescence and flower parts. It ends with a floral diagram and a floral formula.

What do the symbols K, C, A, G and P mean in a floral formula?

K stands for calyx, C for corolla, A for androecium, G for gynoecium and P for perianth. Br means bracteate. A line below G shows a superior ovary and a line above G an inferior ovary.

How are fusion and adhesion shown in a floral formula?

Fusion of members of the same whorl is shown by enclosing the number in a bracket, as in K (5). Adhesion between members of different whorls is shown by a line drawn above their symbols, as over C and A in Solanaceae.

What is shown in a floral diagram?

A floral diagram shows the number of floral parts, their arrangement and their relation to one another. The mother axis is shown by a dot at the top. The calyx is drawn as the outermost whorl and the gynoecium in the centre.

What is the floral formula of mustard?

Mustard belongs to the family Brassicaceae. Its flower is actinomorphic and bisexual, with four sepals in two whorls and four petals. It has six stamens in two whorls of two and four, and two fused carpels with a superior ovary: K 2+2, C 4, A 2+4, G (2).

What are the floral characters of Solanaceae?

Flowers are bisexual and actinomorphic. The calyx has five united, persistent sepals and the corolla five united petals, both valvate. There are five epipetalous stamens. The bicarpellary, syncarpous ovary is superior and bilocular, with axile placentation on a swollen placenta.

What is the economic importance of Solanaceae?

Solanaceae gives food plants (tomato, brinjal, potato), a spice (chilli), medicinal plants (belladonna, ashwagandha), a fumigatory plant (tobacco) and an ornamental plant (petunia). It is commonly called the potato family.

Why is Solanaceae called the potato family?

Solanaceae is commonly called the potato family because the potato, Solanum tuberosum, is its best-known member. The potato is an underground stem. The family is large and widely distributed in the tropics, subtropics and temperate zones.

Previous year questions on Description of Some Important Families

2 questions from past papers, each with a step-by-step solution.

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