Phyla of Ferns and Fern Allies

General Botany Lab

Ferns and Fern Allies General Characteristics:

Contain vascular tissues

Mostly have megaphylls and roots

Reproduce via spores

Sporophyte is the dominant life stage

Lycophyta:

Club Mosses and Relatives

Lycophyta Key Features:

Seedless, reproducing by spores

Have roots and microphyll leaves

Lycophyta Genera:

Lycopodium

Selaginella

Isoetes

Lycopodium:

Homosporous

Spores develop into bisexual gametophytes

Sporophyte with strobili containing sporangia

Selaginella:

Heterosporous

Megaspores develop into female gametophytes; microspores develop into male gametophytes

Isoetes:

Aquatic or semi-aquatic; often called quillworts

Some species exhibit CAM photosynthesis

Monilophyta:

Ferns and Fern Allies

Monilophyta Classes:

Class Equisetophyta

Class Psilophyta

Class Pteridophyta

Class Equisetophyta:

Horsetails

Equisetophyta Key Features:

Stem: ridged, photosynthetic

Leaves: reduced megaphylls in whorls at nodes

Reproductive Structures: Sporangiophores, Strobilus

Equisetophyta Sporangiophores:

Structures that bear sporangia

Equisetophyta Strobilus:

Cone-like structure formed by sporangiophores

Equisetophyta Life Cycle:

Homosporous

Gametophyte produces both archegonia and antheridia

Equisetophyta Homosporous:

Spores germinate into bisexual gametophytes

Class Psilophyta:

Whisk Ferns

Psilophyta Key Features:

Lack true roots and leaves

Stem: Photosynthetic, dichotomously branched

Sporangia: Formed directly on stem segments

Example: Psilotum

Psilophyta Life Cycle:

Homosporous

Gametophyte produces both male and female structures

Psilophyta Homosporous:

Spores develop into gametophytes with rhizoids for anchorage

Class Pteridophyta:

Ferns

Pteridophyta Key Features:

True roots, stems, and large megaphylls (fronds)

Fronds bear sporangia on their undersides, clustered in sori

Sori are often covered by an indusium (protective layer)

Sporangia release spores, which germinate into heart-shaped gametophytes (prothalli)

Gametophytes produce rhizoids for anchorage

Pteridophyta Life Cycle:

1. Diploid sporophyte (dominant) produces haploid spores via meiosis

2. Spores develop into haploid gametophytes

3. Gametophytes produce gametes

4. Fertilization → Zygote → New Sporophyte

Lycopodium Homosporous Life Cycle:

Sporophyte → Strobilus → Spores → Gametophyte (bisexual) → Fertilization → New Sporophyte

Selaginella Heterozygous life cycle:

Sporophyte → Megasporangia and Microsporangia

Megaspores → Female gametophyte

Microspores → Male gametophyte

Fertilization → Zygote → New sporophyte

Equisetum Homosporous Life Cycle:

Sporophyte → Strobilus → Spores → Bisexual Gametophyte → Fertilization → New Sporophyte

Psilotum Homosporous Life Cycle:

Sporophyte → Spores → Gametophyte → Fertilization → New Sporophyte

Ferns Homosporous Life Cycle:

Sporophyte → Sori → Spores → Gametophyte → Fertilization → New Sporophyte