Seedless Plants

Bryophytes

• Not monophyletic (uncertainty in phylogeny)
• Thin, ground-cover plants
• lack of vascular system = can't grow tall

Characteristics of Bryophytes

• Short
• Tissue only a few cells thick
• Dominant phase: Haploid Gametophyte (unlike the rest of plants)
• Sporophyte (2N) is dependent on Gametophyte (1N)
• Plants are male or female
• Sperm move through water (must be moist!)
• Not fully terrestrial yet

Bryophyte Life Cycle

Characteristics of Seedless Vascular Plants

• Have vascular tissue
• Xylem
• moves water
• contains lignin
• formed through programmed cell death
• Phloem
• moves nutrients, minerals and organics through plant
• living tissue
• Products from Roots and Leaves to the rest of the plant
• Allows plants to grow taller
• Roots
• Complex, multicellular
• Anchors plants
• Provides nutrients
• Leaves
• Complex, multicellular
• Enables photosynthesis
• Microphylls: small, single vascular tube
• Megaphylls: large, complex branching vascular system (most plants)
• Greek "phyll" = leaf
• Sporophylls
• Sporangia: modified leaf that produces spores
• Adapted sporollenin walls to protect Sporangia from desiccation

Life Cycle

• Dominant Form: Diploid (2N) Sporophyte
• No longer depends on the Haploid (1N) Gametophyte
• Opposite of bryophytes
• Allows for greater complexity

Diversity of Seedless Vascular Plants

Lycophyta

• ~1200 species
• Fake mosses Examples: Quillworts, Club Mosses, Spike Mosses
• Microphyllous: small leaves
• During Carboniferous period
• small plants and woody trees
• Moist and warm swamps
• Small species persist

Pterophyta

• ~12,000 species
• Much of the diversity has gone extinct Example: Ferns
• Marshy, Wet environment
• Whisk Ferns
• Living fossils
• No roots or leaves
• Horsetails
• Grew to 15m in Carboniferous period
• Only 15 extant species
• True Ferns
• Megaphylls
• Large leaves, extensive branching
• Most successful of seedless vascular plants (~12,000 species)
• Sori: clusters of sporangia on bottom of leaves
• Dispersal through catapult or wind

Coal Swamps

• Derived from Lycophyta and Pterophyta
• Coal: produced from a combo of Swamps + Marine Sediments + Decayed Organic Matter + heat + pressure
• Plants in swamps sequestered large amount of CO2
• 5x less atmospheric CO2
• This produced the fossil fuels we use today

Carboniferous Dry-out

• Environment began to dry
• Plants adapted by making seeds
• Seeds: Embryo with stored food and protection