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Floral formula incudes terms or notations given to different parts or structures of a flower’s body. Concisely, floral formula is representation of flower parts with the help of symbols, numbers, or letters. It is very useful as it serves the purpose of increasing observation and representing a whole diagram of a flower in the simplest form. The floral formula provides the vital information of a flower parts, its arrangement, and the relation that the parts share with one another.
| Letters used in Floral Formula | Denotes |
| K | Calyx – sepal |
| C | Corolla – petals |
| P | Perianth – fussed sepal and petal / tepals |
| A | Androecium – male part, stamens |
| G | Gynoecium – female part, carpels |
| Br | Bract / Bracteates |
| Ebr | Ebracteate flower |
| Brl | Bracteolate flower |
| Ebrl | Ebracteolate flower |
| Epik | Epicalyx |
| N | Neuter |
These parts are drawn in the following successive pattern – Calyx, Corolla, Androecium and Gynoecium in the floral formula.
Question 1. On the basis of the position of which of the following parts a flower corresponding to the ovary on the thalamus can be described as hypogynous, perigynous, and epigynous?
- Calyx
- Corolla
- Androecium
- All of the above
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Ans. d
Explanation. A flower can be decided as hypogynous, perigynous, and epigynous based on the position of all three parts that is calyx, corolla, and androecium corresponding to the ovary on the thalamus. In a hypogynous flower, the ovary is placed above these parts. In a perigynous flower, the ovary is in the centre and in an epigynous flower, the ovary is fused with thalamus and is inferior.
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Read More: Inflorescence in flowering plants
Question 2. In a Floral formula what is shown by overlapping the margins of arcs?
- Aestivation
- Hibernation
- Vegetative
- Cessation
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Ans. a
Explanation. Aestivation is the way the petals and sepals of a flower are arranged before the flower has opened that is in the bud of a flower. It is also known as aestivation. Aestivation is used to determine the taxa of a flower. The various types of aestivations are valvate, twisted, imbricate, and vexillary.
Question 3. Without the differentiation of calyx and corolla, the floral organs which are non-essential are called as
- Lodicules
- Pedicel
- Thalamus
- Perianth
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Ans. d
Explanation. The main whorls of a flower are corolla, calyx, gynoecium, and androecium. A flower is identified on the basis of these parts in a floral formula. All of the mentioned four parts forms the swollen end of the stalk of flowering plant. This is known as thalamus. In some flowers the calyx and the corolla are fused and hence are not distinct. This non-essential and non-differentiated organ in the fused form is known as perianth.
Read More: Triple Fusion in flowering plants
Question 4. A flower is decided as bisexual flower on the –
- Presence of Stamens
- Presence of Pistils
- Presence of both a and b
- Presence of either a or b
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Ans. c
Explanation. Stamens are also known as androecium and Pistils are also known as gynoecium. Pollination is the process through which flowering plants sexually reproduce. A flower containing either of androecium or gynoecium are known as unisexual flowers, e.g., coconut flowers, cucumber, pine, papaya, etc. On the other hand, the flowers which have both androecium and gynoecium are called as bisexual flowers, e.g., lily, brinjal, tomato, mango, tulip, hibiscus, etc.
Read More: Difference between cross pollination and self pollination
Question 5. What is the corolla aestivation of the papilionaceous flower which has a large vexillum covering two wings and its keel covered by another wing?
- Twisted
- Ascending imbricate
- Valvate
- Descending imbricate
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Ans. d
Explanation. The corolla of the papilionaceae family has the shape of a butterfly. The butterfly shape is due to the varying size of the petals. The corolla has 5 petals. The vexillum is the large petal on the posterior-most side. The keel which is covered by the wings of the vexillum is made of the innermost fused petals. The large petals followed by small petals kind of overlapping is seen in the descending order in terms of size. Thus, this arrangement is known as descending imbricate.
Question 6. Which of the following is false about floral formula –
- Indefinite number of floral parts is shown with the help of infinity symbol ‘∞’
- Calyx is denoted with the letter ‘C’
- K5 means there are five petals, aposepalous
- A2+2 means 4, 2 whorls
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Ans. b
Explanation. In the floral formula, calyx (sepals) is denoted as ‘K’ and not ‘C’. it is one of the non-essential organs of the flower, it is the outermost and the first whorl of the flower. In the bud stage of the flower the calyx forms a protective layer around the bud. The ‘C’ in the floral formula is written for corolla. Kn is written for polysepalous calyx while K(n) is written for gamosepalous calyx.
Question 7. Which is the flower represented below in this floral diagram –
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Br Brl ⊕
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P3 + 3 A3 + 3 G(3)
K(3-4) C(3-4) |
K( 5 ) C( 5 ) A(∞) 
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Ans. a
Explanation. The given floral diagram is of hibiscus. As per the floral diagram and formula, hibiscus has the presence of bract and bracteates. It is a radially symmetrical flower. It performs bisexual reproduction. The calyx has 5 sepals. The corolla has 5 petals. There are numerous androecium stamens. It also has superior ovary as the gynoecium is above the calyx, corolla and androecium. It has 5 stigmas.
Read More: Photoperiodism in Plants
Question 8. The characteristic feature of Indigofera is
- Calyx
- Vexillum
- Keel
- Symmetry
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Ans. c
Explanation. Indigofera belongs to the family of Papilionaceae. This is a sub-family of Fabaceae. Fabaceae has bilateral symmetry and shows vexillary aestivation. It has 5 corolla petals. The flower has prominent anterior fused small petal which is known as keel. It is fund at the base. The keel peal is vexillary aestivation which the characteristic feature of Fabaceae family to which Indigofera belongs.
Question 9. Which of the following flowers exhibit radial symmetry?
- Pisum
- Brassica
- Cassia
- Trifolium
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Ans. b
Explanation. Out of the given options, Brassica is the only flower which exhibits distinct radial symmetry. All the petals of the flower are identical in size and shape. The other type of symmetry is the bilateral symmetry which shows symmetry in only one plane. The radial symmetry in plants is a pollination strategy.
Question 10. Among the following which is a perigynous flower?
- Rose
- China rose
- Cucumber
- Guava
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Ans. a
Explanation. Out of the given options, rose is a perigynous flower. Its hypanthium is attached to the receptable below the gynoecium and surrounds the ovary. It has a superior ovary but in the centre of the flower. The petals, sepals, and the stamens are attached to the rim of the hypanthium.
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