Asteraceae Brassicaceae Poaceae

Introduction

Angiosperms represent a large group of seed-bearing vascular land plants. It is the last clade of plants, with around 260,000 species of plants on Earth. It is the most advanced group of plants with several special characteristics. With flowers as one of the unique characteristics of this group, Angiosperms are also called “flowering plants''. Also diverse from Gymnosperms with exposed seeds, this group of plants have enclosed seeds.

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Characteristics of angiosperms

• Presence of a true flower and fruits.

• Carpels fully enclose ovules which get converted to future seeds. The carpels are distinguished into an ovary, style and stigma.

• The embryo sac is embedded in the female sporophytic tissue called nucellus and contains the female gamete or egg.

• Very simple male gametophyte.

• Plants show double fertilization.

• Plants exhibit alternation of generation.

• Plants show heterosporous life cycles.

• Proper organization of the shoot apical meristem.

Asteraceae

Asteraceae is one of the largest angiosperm families consisting of several species of important flowering plants. The other name of this family is Compositae or daisy. Common examples are sunflowers, pansies, lettuce etc.

Characteristics of Asteraceae

• It includes herbs, trees and shrubs.
• Flowers are bisexual or unisexual.
• These plants have composite 'flowers.'
• Flowers are generally well-shaped, with an enormous number of small flowers called florets.
• Androecium is always absent, and gynoecium may either be present or absent in flower.
• They are mostly xerophytes, semi-aquatic and hydrophytes; including trees and shrubs

Importance

• The Asteraceae family serves as a great source of food. Lettuce is an example that is edible.

• Asteraceae also have many medicinal uses. Several plants are used to cure bowel disorders. Juices and roots of Asteraceae plants are also very beneficial to several diseases.

• Some plants can be used as an insecticide in the industry.

• Some of the plants of this group produce oil (e.g. sunflower) which can be used in cooking, aromatherapy etc.

• They are also a good source of fodder.

Examples − Asters, daisy, sunflower, Helianthus tuberosus.

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Brassiceae

With the model plant Arabidopsis thaliana, this group is another diverse group of Angiosperm. With about 375 genera, it is well distributed in the world. Brassicaceae is also known as Cruciferae.

Characteristics of Brassicaceae

• They are generally herbs, shrubs, annuals and biennials.
• Plants are generally mesophytes.
• Stems are generally erect and woody.
• Food is stored in taproots, due to which they are swollen.
• They have a racemose or corymb type of inflorescence.
• Flowers are complete and hermaphrodite.

Importance

• The plants in the Brassicaceae family are generally used as vegetables (e.g Cabbage)
• Most of the seeds of the plants yield oil that can be used for cooking.
• Have got medicinal importance. The plants are used to cure cough, asthma, piles, bronchitis and fever.
• Beautiful flowers are used to make flower jewellery.
• They are a good source of fodder.

Examples − Cabbages, Alyssum, Hesperis, Iberis amara

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Poaceae

Another important family of Angiosperm since it has enormous unique features along with economic and industrial uses.

Characteristics of Poaceae

• Generally are herbs, annuals or perennials or shrubs.
• They are generally grass-like plants with blade-like leaves.
• Roots are basically adventitious, fibrous, branched, fascicled or stilt
• Stems are cylindrical, with nodes and internodes, woody
• Leaves are alternate, simple, distichous, exstipulate, sessile, and ligulate
• Plants generally have compound spike inflorescence which may be sessile or stalked
• The plants bear flowers that are bracteate and bracteolate, sessile, incomplete with 3 stamens and 3 carpels

Importance

• Forms a good source of food. Generally, in most places, the staple food comes from this group.
• Several plants are used as fodder.
• Plants like bamboo and Melocalamus are used in paper and furniture production respectively.
• The plants have medicinal properties. Wheat plants are used in cancer treatment
• Some plants are used as ornamental plants as well

Examples − Rhynchelytrum repens, Cortaderia selloana, Lemon grass, Oryza sativa, Zea mays (Maize)

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Differences of the families of Angiosperms

SL. NO	CHARACTERS	ASTERACEAE	BRASSICACEAE	POACEAE
1	Inflorescence	Composite	Racemose	Spikelet
2	Androecium	Absent	Stamen 6 in numbers	Usually stamens 3 in numbers, rarely maybe 6 sometimes as well
3	Gynoecium	Bicarpellary, if gynoecium is present or it is absent in some cases	bicarpellary ovary	3 numbers of carpel
4	Examples	Sunflower	Mustard plants	Grasses

Conclusion

Angiosperms as known as the flowering plants are the largest and most varied group in Plantae kingdom. The Angiosperm family consists of three different families within itself which are Asteraceae, Brassicaceae and Poaceae are the most important. All the plants in the families have great medicinal values. They are also used in food industries. They are a great influence in economic terms.

FAQs

Q1. What is the significance of Double fertilization?

Ans. The pollen grain, when it becomes a mature microgametophyte, produces a long pollen tube with two sperm nuclei. One nucleus unites with an egg to produce a zygote, whereas the other unites with two other nuclei in the gametophyte to produce an endosperm nucleus. With time, as the embryo develops from the zygote, the endosperm nucleus divides and surrounds the embryo with stored food. Double fertilization also conserves energy.

Q2. Differentiate between Angiosperm and gymnosperm?

Ans. Angiosperms are seed-producing flowering plants whose seeds are enclosed within an ovary. Whereas, gymnosperms are seed-producing non-flowering plants whose seeds are unenclosed. Angiosperms include plants like roses, peas, sunflowers, oaks, and maples. Gymnosperm examples include the non-flowering evergreen trees such as pine and fir.

Q3. What is the importance of Angiosperms?

Ans. Members of several angiosperm families are used as food on a local level. Examples: Cabbage, broccoli etc. They are also used as grains, sugars, vegetables, fruits, oils, nuts, and spices. They are also greatly used in timber, fuel, medicines, and the ornamental industry.

Q4. What are Angiosperms?

Ans. Angiosperms are also called flowering plants which include about 260,000 species of flowering plants It is the largest, most diverse group and most successful group within the kingdom Plantae. Angiosperms alone represent approximately 80% of all the known green plants on earth. The plants are vascular seed plants in which the ovule (egg) is fertilized and develops into a seed in an enclosed hollow ovary.

Q5. What is the industrial importance of Poaceae?

Ans. The family Poaceae is considered one of the most economically important plant families since they produce almost the world’s food staples like bajra, maize etc. The plants under Poaceae also provide forage and building materials. Examples, in this case, are bamboo, straw etc.

Q6. How are gymnosperms classified?

Ans. Coniferophyta, Cycadophyta, Ginkgophyta and Gnetophyta are the four classes under gymnosperms.