The threads in this topic provide a comprehensive overview of cryptogams, a diverse group of organisms characterised by their reproduction through spores rather than seeds, or flowers, earning them the name "hidden marriage." They explore three main categories: Pteridophytes, which include vascular plants like ferns and horsetails known for their ancient lineage and ecological roles in soil stabilisation; Bryophytes, encompassing non-vascular plants such as mosses and liverworts, highlighting their importance in water retention and as pioneering colonisers; and Thallophytes, focusing on lichens (symbiotic fusions of fungi and algae/cyanobacteria), fungi (nature's primary decomposers and recyclers), and slime moulds (unique protists vital for nutrient cycling), all of which play crucial, often unseen, roles in supporting Earth's ecosystems and offering insights into the planet's evolutionary history.

This topic attempts to answer the following questions:

• What are cryptogams, and what is the etymological origin of the term?

• Name the three main groups of cryptogams and provide an example for each.

• How do ferns, as pteridophytes, differ from bryophytes in terms of their physical structure?

• Describe a key adaptation that allows mosses to survive in harsh environmental conditions.

• Explain the symbiotic relationship that forms a lichen.

• Are fungi considered plants? Justify your answer based on their biological characteristics.

• What is the primary ecological role of fungi in an ecosystem?

• Briefly describe the unique feeding mechanism of a slime mould in its plasmodial stage.

• Why are lichens considered important ecological indicators?

• What is the significance of bryophytes in the early evolution of plant life on Earth