What Makes Asteraceae Essential in Biology?
The floral plants are the proof that heaven exists on earth. One of the most beautiful flowering plants with exceptional uses is Asteraceae. This family is also called Compositae and has over 1900 genera along with 32,000 known species. In this family, you will find myriads of trees, shrubs, and herbs. It is also considered one of the largest families of plants in the higher-order. In this article, we will study the botanical features and uses of this vast flowering plant family.
What is Asteraceae?
Asteraceae plants fall in the family Compositae or Asteraceae. It is a wide family comprising many genera and species. The common flowering plants we know falling on this list are asters, daisies, chrysanthemums, dahlias, cosmos, marigolds, etc.
This family also includes ragweed, dandelion, thistle, and other noxious weeds. The other members apart from these flowering plants are lettuce, artichokes, endive, salsify, etc. These are edible species of this family. Some of the flowering plants are also grown as crops such as sunflower and safflower.
Features of Asteraceae
If we look at the Asteraceae family plants list, we will find a distinct flowering arrangement. The flowers are bell-shaped and comprise small flowers known as florets. These compound flowers have leaflets or bracts surrounding the florets. These florets form a bell-shaped disk at the centre. From this centre, the petals come out as rays to form a circular shape.
Some of the species have petals that bend backwards. Some of them only have a disk or ray florets. The sepals of the flowers of the Asteraceae plants are reduced to form a ring of scales, bristles, or hairs. It is cumulatively called pappus. It can be found in the mature fruit these plants produce. The leaves are occasionally compound and generally remain simple in their arrangements. In the stem, they form an alternate opposite arrangement. Sometimes, they are whorled.
As per the paleobotanists, Asteraceae evolved somewhere in South America during the Late Cretaceous Era (approximately 83 million years ago). The fossils date back to Eocene Epoch and show how diversely this family has proliferated.
Features of the Flowers
The outstanding feature of this family is its flowers. The flowers have a distinct set of features that separate this family from the rest. As mentioned earlier, the small florets form an inflorescence that resembles a single flower. It means that the external features of Asteraceae flowers contain a head formed by the conjugation of the smaller florets. The head is then covered outside by modified leaves called bracts.
A corolla is a flat floret that emerges from the head inside the flower. It means that each floret is a smaller flower that forms the head in a group. It means that an inflorescence is the accumulation of over 1000 florets. The head is rather a secondary and complex arrangement called a capitulescence.
Here is a list to summarise the features of this family of flowering plants.
The taproots of these plants are modified to form tubers for storing food and water.
The stems are erect most of the time. They are woody, prostrate, or hairy. Some of the species contain latex.
The structure of the leaves depicts petiolate, radical, and exstipulate features.
The flowers are either ligulate or tubular. They can be unisexual or bisexual in nature. They have united anthers and do not contain filaments.
The androecium is not present, and gynoecium may or may not be present in the flowers.
The seeds are virtually non-endospermic in nature as they reserve food in two cotyledons.
(Image will be Uploaded soon)
Economic Importance of Asteraceae
Food
This family is an important source of food. The roots and leaves of Helianthus tuberosus and Lactuca sativa are edible. There are other species that are grown as food crops, as the nutritional value of the plant parts is remarkable.
Oil
The Asteraceae examples that produce oil are sunflower and safflower. This oil is used for cooking. Many other species produce essential oils that are used for aromatherapy. These essential oils contain derivatives of terpenoids. These oils also contain secondary metabolites such as flavonoids. These molecules have anti-amebic properties and can reduce the infection caused by Leishmania, Trypanosoma, and Plasmodium.
Animal Fodder
Another good use of the leftover plants is using them as animal fodder. After the extraction of cooking oil, the cake is used as an excellent nutritional source for the cattle.
Medicinal Values
Most of the species belonging to the Asteraceae family have medicinal values. For example, Artemisia is used for bowel disorders as it produces santonin. This compound has a cooling effect and provides relief in digestive issues and other bowel disorders.
Some of the species are used to provide relief in asthma. The plant extracts can also be used for curing bleeding piles and cough. These compounds can also act as stimulants and appetisers, helping people to maintain a proper diet.
Ornamental Purposes
The flowers are widely used for ornamental purposes. The venues of the occasions are decorated using these flowers. This is why the species producing extraordinary flowers with brilliant colour combinations are grown as ornamental crops. Alyssum, Hesperis, Iberis, etc., are used for such requirements.
Conclusion
This is all you need to know about the botanical features and uses of Asteraceae. Understand the Asteraceae characteristics and determine the difference of this family with the rest of the higher-order flowering plants. Check out the names of the plants in the Asteraceae family PDF and understand the features of these plants described.
FAQs on Asteraceae: Features, Uses, and Significance
1. What is the Asteraceae family also known as, and why?
The Asteraceae family is also commonly known as the Compositae family. The name 'Compositae' refers to the most distinctive feature of the family: its 'composite' flower head. What appears to be a single large flower, like a sunflower or daisy, is actually a compact inflorescence made up of numerous small flowers called florets.
2. What are some common examples of plants from the Asteraceae family?
The Asteraceae family is one of the largest families of flowering plants and includes many well-known species. Common examples include:
- Ornamental plants: Sunflower (Helianthus annuus), Marigold (Tagetes), Dahlia, and Chrysanthemum.
- Edible plants: Lettuce (Lactuca sativa), Artichoke, and Chicory.
- Common weeds: Dandelion (Taraxacum) and Thistle.
- Medicinal plants: Chamomile and Echinacea.
3. What is the unique type of inflorescence found in the Asteraceae family called, and how is it structured?
The unique inflorescence characteristic of the Asteraceae family is called a capitulum or head. This structure consists of many small, stalkless flowers (florets) arranged on a flattened, disc-like receptacle. The entire head is surrounded by a whorl of protective bracts called an involucre, making it look like a single flower.
4. What is the difference between ray florets and disc florets in an Asteraceae flower head?
Ray florets and disc florets are the two main types of flowers found within the capitulum of an Asteraceae plant.
- Ray Florets: These are typically found on the periphery of the head. They are zygomorphic (bilaterally symmetrical) and often sterile or pistillate (female). Their most prominent feature is a large, strap-shaped petal (ligule) that resembles the petal of a simple flower, serving to attract pollinators.
- Disc Florets: These are located in the central part of the head. They are actinomorphic (radially symmetrical), tubular in shape, and usually bisexual. These are the fertile flowers responsible for producing seeds.
5. What is the floral formula for the two types of florets in the Asteraceae family?
The floral formulas for the ray and disc florets differ due to their structure. Following the CBSE/NCERT pattern for the 2025-26 session, the typical formulas are:
- Ray Floret (Zygomorphic and Pistillate): % Kpappus C(5) A0 G(2), inferior ovary.
- Disc Floret (Actinomorphic and Bisexual): ⊕ Kpappus C(5) A(5) G(2), inferior ovary.
6. Why do some Asteraceae plants, like Dahlias, develop tubers?
Certain perennial plants in the Asteraceae family, such as Dahlia and Jerusalem artichoke, develop tubers as specialized underground storage organs. These tuberous roots store food, primarily in the form of carbohydrates like inulin. This stored energy allows the plant to survive unfavourable conditions like winter or drought and to regrow quickly in the next growing season.
7. What type of fruit is characteristic of the Asteraceae family?
The characteristic fruit of the Asteraceae family is a cypsela. It is a dry, single-seeded fruit that develops from an inferior, bicarpellary ovary. A key feature of the cypsela is that it is often crowned with a persistent pappus (the modified calyx), which acts like a parachute to aid in wind dispersal of the seed.
8. How does the composite flower head of Asteraceae improve its chances of pollination?
The composite flower head (capitulum) provides a significant evolutionary advantage for pollination. Firstly, the large cluster of florets creates a prominent visual display that is much more attractive to pollinators than a single small flower would be. Secondly, an insect visiting the head can pollinate dozens of individual florets in a single visit, making the process highly efficient. This increases the overall chances of successful fertilisation and seed set for the plant with minimal energy expenditure per flower.
