PRELIMS

Botany Classification: Cryptogams

Botany is the study of different types of trees and plants (Theophrastus is the Father of Botany). In 1883, Eichler classified the plant kingdom into two major groups.

Eichler's Classification (1883)

1. Cryptogamus (Non-flowering): No flowers or seeds.
   • Thallophyta: Algae, Fungi.
   • Bryophyta: Amphibians of the plant kingdom.
   • Pteridophyta: First land plants with vascular tissue.
2. Phanerogamus (Flowering): Seed-bearing plants.
   • Gymnosperms: Naked seeds.
   • Angiosperms: Enclosed seeds (Monocots / Dicots).

I. Thallophyta: Algae and Fungi

Largest group of the plant kingdom; body not differentiated into root, stem, or leaves (Thallus); no conducting tissue.

1. Algae (Phycology):
   • Contain chlorophyll; autotrophic.
   • Useful Algae:
     • Food: Porphyra, Ulva, Nostoc.
     • Iodine Source: Laminaria, Fucus.
     • Manure: Anabina, Kelp.
     • Space Algae: Chlorella (astronauts get protein, water, and from it).
2. Fungi (Mycology):
   • Chlorophyll-less; cell wall made of Chitin; reserve food is Glycogen.
   • Plant Diseases: White rust (Crucifer), Loose smut (Wheat), Red rot (Sugarcane), Tikka disease (Groundnut).

II. Bryophyta: The "Amphibians"

First group of land plants; lack xylem and phloem; lack true roots/stems.

• Sphagnum Moss: Can soak water 18 times its weight; used by gardeners to prevent drying during transport. Used as fuel and antiseptic.

III. Pteridophyta: The First Vascular Plants

Found in wet, shady places; differentiated into root, stem, and leaves; possess conducting tissues (but xylem lacks vessels and phloem lacks companion cells).

• Examples: Ferns, Azolla, Lycopodium.

Lichens (Symbiotic Association)

A Lichen is a symbiotic association between an Algae (or Cyanobacteria, provides food via photosynthesis) and a Fungus (provides shelter/absorbs water and minerals). Considered good indicators of air pollution (Sulphur dioxide) due to their sensitivity — hence called "Pollution Indicators".

UPSC Relevance

Botany is a major contributor to GS-III Science (Agriculture/Forestry).

• Unique Features: The "Amphibian" nature of Bryophytes and the "Thallus" structure of Algae/Fungi are favorite classification questions.
• Space S&T: The role of Chlorella as an life-support system in space missions.
• Fungal Diseases: Identifying Red rot (Sugarcane) or Tikka disease (Groundnut) is critical for agrarian/environmental contexts.