Decompose rocks, making substrate suitable for higher plants.

Form dense mats on soil, reducing impact of rain and preventing soil erosion.

Divisions: Liverworts and Mosses.

Habitat: Moist, shady habitats (banks of streams, marshy ground, damp soil, bark of trees, deep in woods).
Plant body: Thalloid (e.g., $Marchantia$).
- Thallus is dorsiventral and closely appressed to substratum.
- Leafy members have tiny leaf-like appendages in two rows on stem-like structures.
Asexual reproduction:
- Fragmentation of thalli.
- Formation of specialized structures called gemmae (sing. gemma).
  - Gemmae: Green, multicellular, asexual buds.
  - Develop in small receptacles called gemma cups on thalli.
  - Detach from parent body and germinate to form new individuals.
Sexual reproduction: Male and female sex organs produced on same or different thalli.
Sporophyte differentiated into a foot, seta, and capsule.
Spores produced within capsule after meiosis. Spores germinate to form free-living gametophytes.

Predominant stage: Gametophyte, consists of two stages:
- Protonema stage: First stage, develops directly from a spore. Creeping, green, branched, frequently filamentous.
- Leafy stage: Second stage, develops from secondary protonema as a lateral bud. Upright, slender axes with spirally arranged leaves. Attached to soil by multicellular and branched rhizoids. Bears sex organs.
Vegetative reproduction: Fragmentation and budding in secondary protonema.
Sexual reproduction: Sex organs (antheridia and archegonia) produced at apex of leafy shoots.
After fertilization, zygote develops into a sporophyte (foot, seta, and capsule).
Sporophyte in mosses is more elaborate than in liverworts.
Capsule contains spores. Spores formed after meiosis.
Elaborate mechanism of spore dispersal.
Common examples: $Funaria$, $Polytrichum$, $Sphagnum$.

Include horsetails and ferns.
Uses: Medicinal purposes, soil-binders, ornamentals.
Evolutionary significance: First terrestrial plants to possess vascular tissues (xylem and phloem).
Habitat: Cool, damp, shady places; some flourish in sandy-soil conditions.
Dominant phase: Sporophyte (in bryophytes, it's gametophyte).
Main plant body: Sporophyte, differentiated into true root, stem, and leaves. Possess well-differentiated vascular tissues.
Leaves:
- Small (microphylls) as in $Selaginella$.
- Large (macrophylls) as in ferns.
Sporangia: Borne on sporophytes, subtended by leaf-like appendages called sporophylls.
Strobili or cones: In some cases, sporophylls form distinct compact structures (e.g., $Selaginella$, $Equisetum$).
Sporangia produce spores by meiosis in spore mother cells.
Spores germinate to give rise to inconspicuous, small but multicellular, free-living, mostly photosynthetic thalloid gametophytes called prothallus.
Prothallus requirements: Cool, damp, shady places to grow.
Limited spread: Due to specific requirements and need for water for fertil