Floral  Diagram and Formula

Floral Diagram:

The diagram that illustrates the relative position and number of parts present in each whorl in a flower is termed the floral diagram. It provides information about the number of parts of a flower, their arrangement, and the relation they share.

floral diagram

Floral diagram of Brassicaceae

The diagram is mostly drawn based on the position of the mother axis concerning the flower which is represented as a dot on the top of the floral diagram. The calyx, corolla, androecium, and gynoecium to drawn in successive whorls, as the calyx is placed outermost and the gynoecium is in the center.

Floral Formula:

It is an expression that summarizes the information given in the floral diagram, in the form of an equation.

Based on morphological features, used to describe a flowering plant with its habit, and vegetative characteristics -root, stem and leaves, inflorescence, and flower parts, a floral formula and diagram are presented. In a floral formula, the following symbols are used, these are listed in the given picture:

symbols used in floral formula

Symbols used in a floral formula

In the floral formula, the cohesion is shown as within parts of whorls, and adhesion is shown as between whorls.

Floral Diagram and Formula of Some Important Plant Families with Characteristic Features:


The family is earlier known as Papilionoideae, a subfamily of the family Leguminosae it is found all over the world.

Vegetative characters of Fabaceae:

  • Trees, shrubs, herbs; roots with root nodules
  • Stem: The stem is erect or climber
  • Leaves: These are alternate, pinnately compound or simple; leaf base, pulvinate; stipulate; and the venation is reticulate

Floral characters

  • The Inflorescence: racemose type
  • The Flower: bisexual, zygomorphic flowers
  • Calyx: sepals five, gamosepalous; valvate/imbricate aestivation
  • Corolla: petals five, polypetalous, papilionaceous, consisting of a posterior standard, two lateral wings, two anterior ones forming a keel (enclosing stamens and pistil), vexillary aestivation
  • Androecium: ten, diadelphous, anther dithecous
  • Gynoecium: ovary superior, mono-carpellary, unilocular with many ovules, style single
  • Fruit: legume;
  • seed: one to many, non-endospermic

Floral Diagram and formula:

Floral diagram and formula of Fabaceae

Floral diagram and formula of Fabaceae

Economic importance: These are used as ornaments, oils, and edible plants.

  1. Ornaments:
    • Aparajit, Clitoria ternatea
    • Indian coral tree- Erythrina indica
    • Sweet pa- Lathyrus odoratus
    • Japanese pagoda tree- Spora japonica
  2. Edible plants:
    • Arhar (pigeon pea)- Cajanus cajan
    • Chana (Gram, Chickpea)- Cicer arientium
    • Soya (soya bean)- Glycine max
    • Matar (Garden pea)- Pisum sativum
    • French bean- Phaseolus vulgaris etc.

It is a large family, also known as the ‘potato family’. This family is widely distributed in the tropics, subtropics, and also in temperate zones.

Vegetative Characters of Solanaceae:

  • Plants mostly herbs, shrubs, and rarely small trees
  • Stem: The stem is herbaceous rarely woody, aerial; erect, cylindrical, branched, solid or hollow, hairy or glabrous, the underground stem is also found in potato (Solanum tuberosum).
  • Leaves: Leaves are  alternate, simple, rarely pinnately compound, exstipulate; venation -reticulate

Floral Characters

  • Inflorescence: Solitary, axillary, or cymose as in Solanum
  • Flower: bisexual, actinomorphic
  • Calyx: sepals five, united, persistent, valvate aestivation
  • Corolla: petals five, united; valvate aestivation
  • Androecium: stamens five, epipetalous
  • Gynoecium: bi-carpellary obligately placed, syncarpous; ovary superior, bilocular, the placenta is swollen with many ovules, axile
  • Fruits: berry or capsule
  • Seeds: many, endosperms

Floral Diagram and Formula:

Floral diagram and formula of family Solanaceae

Floral diagram and formula of family Solanaceae

economic importance:

  1. Ornament:
    • Day Jasmine- Castrum diumum
    • Night Jasmine – C. nocturnum, Petunia axillaries
  2. Edible parts:
    • tomato- Lycopersicon esculentum
    • Potato- S. tuberosum
  3. Medical use:
    • Atropa belladonna, ashwagandha
    • Solanum nigrum
  4. Other uses like – tobacco (Nicotiana tabaccum)- Used for smoking, chewing etc.

These are commonly called the ‘Lily family’ which is a characteristic representative of monocotyledonous plants. It is distributed worldwide.

  • Vegetative characters: These are mostly perennial herbs with underground bulbs/corms/ rhizomes
  • Leaves: The leaves are mostly basal, alternate, linear, exstipulate with, and parallel venation is found.

Floral characters:

  • Inflorescence: solitary / cymose; often umbellate clusters
  • Flower: bisexual; actinomorphic, trimerous
  • Perianth tepal six (3+3), often united into a tube; valvate aestivation
  • Androecium: stamen six, 3+3, epitepalous
  • Gynoecium: tricarpellary, syncarpous, ovary superior, trilocular with many ovules;
  • Placentation: axile placentation, Stigma trifid.
  • Fruit: capsule, or rarely as berry
  • Seed: endospermous

Floral diagram and formula:

Floral diagram and formula of Liliaceae

Floral diagram and formula of Liliaceae

Economic importance:

  1. Ornaments:
    • Glory lily- Gloriosa superba
  2. Food:
    • Onion- Allium cepa (also used as medicine)
    • Garlic- A. sativum
    • Satawar- Asparagus recemosus
  3. Other – Colchicum autumnate– Colchicine (an alkaloid obtained is used to induce polyploidy)
Family Cruciferae: (Brassicaceae)

floral characters:

  • Flowers are ebracteate.
  • Calyx– Sepals- 4, free
  • Corolla- Petals 4, Polypetalous and cruciform.
  • Androecium: stamens 6, tetradynamous
  • Gynoecium: bi-carpellary, syncarpous ovary superior with a false partition (replum), Placentation is parietal
  • Fruit– a siliqua or silicula

Floral diagram and formula:

floral diagram Brassicaceae

floral diagram Brassicaceae

Economic importance of Brassicaceae: 

  1. Ornaments
    • Basket of Gold- Alyssum saxatile
    • Candytuft- Iberis amara
    • Wallflower- Cheiranthus cheirl
  2. Edible plants
    • Yellow mustard- Brassica campestris
    • Cauliflower- b. oleracea
    • Radish- Raphanus sativus, etc.

(You can see the post of fruit and its edible part for the information of part of the fruit we eat)

Poaceae: (grass family)- Graminaceae

Inflorescence: Spike or spikelets or panicle of spikelets.

  • Presence of glumes covering spikelets.
  • Inner and outer Palea are present, which represent bract and bracteoles respectively.
  • Perianth 2-3 reduced, translucent, or succulent scaly structures are called lodicules.
  • Androecium: Stamen 3 or some times 6 (3+3)
  • Gynoecium: Monocarpellary, unilocular with a single ovule and two feathery stigmas present.

Floral diagram and formula:

Floral diagram and formula of Poaceae

Floral diagram and formula of Poaceae

Economic Importance:

Staple food grains:

    • Cereals: Wheat- Triticum aestivum, Maize- Zea mays, Rice- Oryza sativa, Oat- Avena sativa, Barley- Hordeum vulgare
    • Millets: Jowar- sorghum vulgare,  Sugar plant- Sugar cane- Saccharum officinarum, etc.


You can also read:


Sexual Reproduction in Flowering Plants

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1 Comment

Plant kingdom-Angiosperms - PCSSTUDIES % Biology · May 15, 2021 at 5:23 pm

[…] Fabaceae– (Papilionaceae) Pea family, which includes all pulses. […]

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