Seedless Vascular Plants
Ferns & Lycophytes
Chapter 23
Seedless Vascular Plants
2 Groups
• Ferns
– Whisk Ferns
– Horsetails
– Ferns
• Lycophytes
– Club Mosses
– Spike Mosses
– Quillworts
Evolution from Bryophytes to
Seedless Vascular Plants
• Development of Vascular Tissue
– Xylem – conducts water and dissolved
minerals
– Phloem – conducts dissolved sugar
• Vascular tissue allows for taller plants
• Dominant sporophyte generation
• Reproduction still depends on water to
transport sperm
• Evolution of True Leaves
Evolution of True Leaves
2 Types of True Leaves
• Microphylls
– Type of leaf found in lycophytes
– Contains one vascular strand
• Megaphylls
– Type of leaf found in ferns, horsetails, and seed
plants
– Contains multiple vascular strands (branched)
– Probably evolved from the webbing of side
branches
Evolution of True Leaves
Ferns
• Phylum Pteridophyta
– Remember: “I’m Terrified of Ferns”
– Seedless - Reproduce by spores produced in
sporangia
– Spores are homosporous
• Give rise to bisexual gametophytes
– Vascular
– Undergo alternation of generations
• Dominant Sporophyte Generation
• Gametophyte generation (prothallus)
– Includes ferns, whisk ferns, and horsetails
Ferns
• An ancient group of plants
• Very diverse group
Parts of a Fern
• Rhizome – horizontal
underground stem
• Frond- megaphyll leaf
• Fiddlehead – young,
tightly coiled frond
• Sporangia – spore cases
• Sori – clusters of
sporangia on bottom side
of frond
Fiddleheads
Sori
Fern Life Cycle
Prothallus – Fern Gametophyte
Whisk Ferns
• Exhibit Dichotomous
branching
• Genera: Psilophyta
Horsetails
• Have hollow, jointed
stems
• Stems contain silica
• Wet, marshy
habitats
• Genera:
Equisetophyta
Lycophytes
• Phylum Lycopodiophyta
– Remember: “I Like-o-Fight with Clubs &
Spikes, & go for the Quill”
– Seedless – Reproduce by spores
• Spores can be heterosporous
– 2 types of n spores –
» megaspores (form a female gametophyte)
» microspores (form a male gametophyte)
– Vascular
– Dominant Sporophyte generation
– Includes Club Mosses, Spike Mosses, &
Quillworts
3 Groups of Lycophytes
1. Club Moss
– True roots
– Rhizomes & erect or trailing aerial stems
– Small, scale-like microphyll leaves
3 Groups of Lycophytes
2. Spike Moss
– Long, creeping rhizomes
•
Typically branch dichotomously
– Roots branch dichotomously
– Overlapping, scale-like microphylls
Resurrection Plant
3 Groups of Lycophytes
3. Quillwort
– Underground corm
•
A short, swollen underground stem
– Cylindrical, quill-like microphyll leafs
– Roots
Ecological & Economic Impacts
• Ferns & Lycophytes
– Help form soil
– Prevent soil erosion
• Branching underground rhizomes and roots or
rhizoids hold soil in place
– Coal deposits
• Formed by remains of ancient ferns
• Powered Industrial Revolution of 19th Century
• Used today to produce electricity