Cryptogams & Classifications | Botany Optional for UPSC PDF Download

Cryptogams

Cryptogams are a diverse group of plants that have long fascinated botanists and nature enthusiasts alike. They are unique in that they do not produce flowers or seeds for reproduction. Instead, cryptogams rely on alternative methods of propagation, such as spores. 

Classification of Cryptogams

Traditionally the Cryptogams are grouped into Thallophyte, Bryophyte and Pteridophyte. 

• Thallophyte includes algae, fungi, etc. 
• The Bryophytes include liverworts, hornworts and mosses.
• Pteridophytes include ferns and their allies.

Division of Cryptogams

Thallophyta

• Thallophytes encompass plants or plant-like organisms, such as algae and fungi, that lack distinct stems, leaves, and roots. The term "thallos" in Greek signifies undifferentiated, and "phyton" means plant.
• Algae reproduce through sexual or asexual means, or sometimes both. Asexual reproduction involves generating offspring without cell or nuclear fusion. Smaller algae typically reproduce asexually via cell division or fragmentation, while larger algae use spores for reproduction.
• Fungi, on the other hand, reproduce sexually and/or asexually. Perfect fungi engage in both sexual and asexual reproduction, while imperfect fungi solely rely on asexual reproduction through mitosis. In both cases, fungi produce spores for dispersal, which can be carried by wind or attached to animals. Fungal spores are smaller and lighter than plant seeds.

Bryophyta

• "Bryophyte" is the collective term for mosses, hornworts, and liverworts, and "bryology" is the study of bryophytes. Mosses typically have leaves growing from stems, and some species exhibit solid-stalked spore capsules growing from the leafy part, while others have stalkless spore capsules.
• Hornworts, in contrast, lack leafy structures and primarily consist of a greenish, flattened sheet with a thallose growth habit. In hornworts, the spore capsules resemble thin, tapering "horns" or needles growing from the thallose part.
• Bryophytes can reproduce both sexually and asexually. They lack pollen and flowers, relying on water for the transportation of male sperm to female eggs. Spore capsules are produced after fertilization of the female egg by a male gamete (sperm). Spore dispersal in bryophytes is primarily achieved through wind.

Pteridophyte

• Pteridophytes, commonly known as ferns or fern allies, are ancient plants. Approximately 9% of the world's pteridophytes are found in India, covering only 2.5% of the world's landmass. Ferns and fern allies constitute the second-largest group of plants in the Indian flora.
• Pteridophytes are among the earliest vascular land plants, mostly terrestrial, thriving in cool, shaded environments. Some pteridophytes adapt to xerophytic, semi-aquatic, and aquatic conditions.
• These plants lack flowers and seeds, relying on spores for reproduction, although vegetative reproduction is also common. Pteridophytes have economic importance, with approximately 170 species used for various purposes such as food, flavoring, dyes, medicines, biofertilizers, oil, fibers, and biogas production.

Conclusion

In conclusion, cryptogams, with their diverse and intriguing characteristics, are essential components of our natural world. They not only offer unique insights into the plant kingdom but also play crucial roles in sustaining our environment. Understanding and appreciating these non-flowering plants enriches our comprehension of biodiversity and the delicate balance of nature.