Floral Families: Malvaceae, Cruciferae - NEET PDF Download

What is Malvaceae?

The Malvaceae family, commonly referred to as the mallow family, is a prominent family within the order Malvales. It encompasses around 244 genera and over 4225 species. The family is distributed in tropical, subtropical, and temperate regions. Members of this family are diverse, ranging from herbs and shrubs to trees and are known for their economic importance, particularly species like cotton and various ornamental plants like hibiscus.

Malvaceae

Vegetative Characters of Malvaceae

Identifying plants means you need to know some basic structural features about important plants. This includes understanding their roots, stems, and the way their leaves look and how they're arranged.

(a) Stem

Stems in the Malvaceae family are typically erect and can be either herbaceous or woody. They often have a hairy surface, with stellate (star-shaped) or simple hairs, which is a distinctive feature of the family.

(b) Leaves

The leaves of Malvaceae plants are usually alternate, though they can sometimes be opposite. They are characteristically palmately lobed or veined and possess stipules. The leaves are generally petiolate, and the margins can be serrate, crenate, or entire.

Floral Characters of Malvaceae

(a) Inflorescence

The inflorescence in Malvaceae is typically axillary. The flowers can be solitary or grouped in various arrangements such as cymes, panicles, or clusters.

(b) Flower

Flowers in the Malvaceae family are usually actinomorphic (radially symmetrical) and hermaphroditic. They are often large and showy, which aids in pollinator attraction.

(c) Calyx

The calyx is composed of 5 (or more) sepals, often fused at the base. An additional outer whorl of bracts, called an epicalyx, is sometimes present and can be mistaken for sepals.

(d) Corolla

The corolla typically has 5 petals, which are usually fused at the base. The petals are often brightly colored, aiding in the attraction of pollinators.

(e) Androecium

The androecium generally consists of numerous stamens. These stamens are often fused into a tube that encircles the pistil, a condition known as monadelphous.

(f) Gynoecium

The gynoecium is typically made up of multiple carpels that are united to form a single compound ovary. The ovary is usually superior with axile placentation.

(g) Fruits

The fruit in Malvaceae can vary, but they are often schizocarps (a dry fruit that splits into single-seeded parts when ripe) or capsules.

(h) Seeds

(i) Floral Formula

A typical floral formula for the Malvaceae family is:

Floral Formula of Malvaceae

This represents a radially symmetrical flower with 5 fused sepals, 5 petals, numerous stamens fused into a tube, and a superior ovary with 5 or more carpels.

Economic Importance of Malvaceae

The Malvaceae family has a significant economic impact due to its diverse applications:
(i) Agriculture

• Cotton (Gossypium spp.) is the most economically important genus, providing the primary natural fiber for the textile industry. Okra (Abelmoschus esculentus) is widely cultivated for its edible green pods.

(ii) Ornamental Plants

• Many species, such as those from the genera Hibiscus, Malva, and Alcea, are cultivated for their attractive flowers and are used in landscaping and garden design.

(iii) Medicinal Uses

• Several members of the Malvaceae family have been used traditionally for their medicinal properties. For instance, the common mallow (Malva sylvestris) is known for its soothing and anti-inflammatory effects.

(iv) Other Uses

• Some species are used for their edible seeds and leaves, while others are utilized for their oil or as a source of natural dyes.

What is Cruciferae (Brassicaceae)?

Cruciferae Family

Vegetative Characters of Cruciferae

Identifying plants means you need to know some basic structural features about important plants. This includes understanding their roots, stems, and the way their leaves look and how they're arranged.

(a) Stem

The stems in the Cruciferae family are typically erect and herbaceous, although some members can be woody. They can be simple or branched and often contain watery sap.

(b) Leaves

Leaves of Cruciferae plants are generally alternate, rarely opposite, without stipules. They can be simple or pinnately compound and often have a waxy or glaucous coating. The leaf margin can be entire, toothed, or lobed.

Floral Characters of Cruciferae

Floral characters include inflorescence, Flower, Calyx, Corolla, Androciem, Gaynocieum, fruits, Seeds and floral formula. details of each character is provided below: 

(a) Inflorescence

The inflorescence is typically a raceme, which is an unbranched, indeterminate type of inflorescence bearing pedicellate flowers along its axis.

(b) Flower

Flowers in the Cruciferae family are actinomorphic (radially symmetrical) and hermaphroditic. They are usually small and not very showy, with four free petals arranged in a cross, which is a distinctive feature of the family.

(c) Calyx

The calyx consists of four free sepals, which are often erect and sometimes saccate at the base.

(d) Corolla

The corolla has four petals arranged in a cross shape, hence the name Cruciferae. The petals are typically clawed at the base.

(e) Androecium

The androecium consists of six stamens, four of which are long and two are short (tetradynamous condition). This is a characteristic feature of the family.

(f) Gynoecium

The gynoecium is composed of two carpels fused to form a single compound ovary, which is superior. It typically has two locules with a false septum called a replum.

(g) Fruits

The fruit is typically a silique or silicle, which is a dry dehiscent fruit that splits open at maturity. The presence of a replum is a distinguishing feature.

(h) Seeds

Seeds are generally small, round, and can be flat or plump. They are usually not endospermic.

(i) Floral Formula

A Typical Floral Formula of Cruciferae family is: 

This represents a flower with four sepals in two whorls, four petals, six stamens (four long and two short), and a superior ovary with two carpels.

Economic Importance of Cruciferae

The Cruciferae family has significant economic value due to its diverse applications:

(i) Agriculture

• Many species are cultivated as vegetables, including cabbage (Brassica oleracea), broccoli (B. oleracea var. italica), cauliflower (B. oleracea var. botrytis), and turnip (B. rapa).

(ii) Oil Production

• Some members like rapeseed (B. napus) and mustard (B. juncea) are grown for their seeds, which are a source of vegetable oil.

(iii) Ornamental Plants

• Several species are used as ornamentals, such as the wallflower (Erysimum) and stock (Matthiola).

(iv) Medicinal Uses

• Some members of the family have been used traditionally for their medicinal properties. For example, mustard seeds are used in poultices and plasters.

(v) Other Uses

• The family also includes model organisms for scientific research, such as Arabidopsis thaliana, which is widely used in plant genetics and molecular biology.