Solanaceae Family: Floral Formula, Floral Diagram, Characteristics and Examples

The Solanaceae family, commonly known as the nightshade family, is a large and economically important group of flowering plants. Members of this family include major food crops, medicinal plants, ornamental species, and some poisonous plants. These plants are widely distributed across tropical, subtropical, and temperate regions, with maximum diversity in Central and South America. The family is easily recognized by its floral structure, presence of alkaloids, and characteristic fruit types such as berries and capsules.

Systematic Position of Solanaceae

The solanaceae family includes well-known plants like tomato, potato, chilli, brinjal, tobacco, petunia, and belladonna. The classification of the Solanaceae family is given below:

Floral Diagram of Solanaceae

The floral diagram of solanaceae shows:

• five fused sepals

• five fused petals

• five epipetalous stamens

• bicarpellary ovary

• axile placentation

• superior ovary

The diagram is circular and pentamerous.

Solanaceae Family Characteristics

The solanaceae family characteristics include distinct vegetative and floral features that help identify members of this family.

Habit

Plants belonging to this family show different growth forms:

• Mostly herbs (Solanum nigrum)

• Some shrubs (Datura)

• Few climbers (Solanum dulcamara)

• Rarely small trees (Cestrum)

Many members contain alkaloids which may be medicinal or poisonous.

Habitat

Plants grow in diverse habitats such as:

• cultivated fields

• gardens

• forests

• tropical regions

• temperate climates

Most species prefer warm climates.

Vegetative Characters of Solanaceae

1. Root

The root system is usually tap root with lateral branches. In some species, storage modifications occur. For example, a potato has an underground tuber which is a modified stem.

2. Stem

Stem characteristics include:

• erect or climbing

• branched

• herbaceous or woody

• cylindrical or angular

• sometimes hairy

Some species show underground modifications.

3. Leaves

Leaves show typical features:

• simple leaves

• alternate arrangement

• exstipulate (no stipules)

• reticulate venation

• entire or lobed margins

Leaves often produce a distinct smell when crushed.

Floral Characteristics of Solanaceae

The floral features are very important for identification.

1. Inflorescence

Inflorescence is usually cymose. It may be:

• solitary

• axillary

• dichasial cyme

• mixed cyme

Flowers may also appear solitary.

2. Flower

Flowers of solanaceae family are:

• bisexual

• actinomorphic

• complete

• pentamerous

• hypogynous

• pedicellate or sessile

These features help identify the family.

3. Calyx

Calyx characteristics:

• 5 sepals

• gamosepalous

• persistent

• valvate aestivation

The calyx often remains attached to fruit.

4. Corolla

Corolla features:

• 5 petals

• gamopetalous

• funnel shaped or tubular

• valvate aestivation

• showy and colored

This is important for pollination.

5. Androecium

Androecium characteristics:

• 5 stamens

• epipetalous

• anthers dithecous

• basifixed

• longitudinal dehiscence

Stamens are attached to corolla.

6. Gynoecium

Gynoecium features:

• bicarpellary

• syncarpous

• superior ovary

• bilocular

• axile placentation

• many ovules

Style is simple and stigma is bilobed.

Floral Formula of Solanaceae

The floral formula of solanaceae is:

⚥ ⊕ K(5) C(5) A5 G̲(2)

Explanation:

• ⚥ → bisexual flower

• ⊕ → actinomorphic symmetry

• K(5) → gamosepalous calyx

• C(5) → gamopetalous corolla

• A5 → five stamens

• G̲(2) → bicarpellary superior ovary

This formula is commonly asked in NEET.

Fruit and Seeds of Solanaceae

1. Fruit

Fruit is usually:

• berry (tomato, brinjal)

• capsule (Datura, Petunia)

The berries are fleshy while the capsule is dry.

2. Seeds

Seed characteristics:

• numerous seeds

• flattened seeds

• endospermic

• embryo curved

These features help seed dispersal.

Solanaceae Family Examples

Some important solanaceae family examples include:

• Tomato (Solanum lycopersicum)

• Potato (Solanum tuberosum)

• Brinjal (Solanum melongena)

• Chilli (Capsicum annuum)

• Tobacco (Nicotiana tabacum)

• Petunia (Petunia hybrida)

• Belladonna (Atropa belladonna)

These are commonly studied examples.

Economic Importance of Solanaceae

The solanaceae family is economically important.

1. Food crops

Many members are vegetables:

• tomato

• potato

• chilli

• brinjal

These are staple foods worldwide.

2. Medicinal plants

Some species contain alkaloids:

• Atropine

• Nicotine

• Scopolamine

Used in medicine.

3. Ornamental plants

Some members are ornamental:

• Petunia

• Solanum

• Brugmansia

Used in gardens.

4. Poisonous plants

Some plants are toxic:

• Belladonna

• Datura

Contain strong alkaloids.