Characteristics of Pteridophytes

• Vascular tissue present

– Phloem and xylem

• Branched sporophytes

• No seeds

• No flowers

• Dominant generation: Sporophyte

4 groups of Pteridophytes

Phylum Psilophyta- Psilopsids/whiskferns

Phylum Lycophyta – Clubmosses

Phylum Sphenophyta – Sphenopsids/

horsetail

Phylum Pterophyta - Ferns

Phylum Psilophyta- Whiskferns

so called because of whisklike stems

leafless, dichotomously branched stems.

Phylum Psilophyta

Class Psilopsida

Order Psilotales

Family Psilotaceae

Genera:Psilotum

Tmesipteris

Sporophyte of Psilotum nudum

Rhizoids

Aerial photosynthetic

stem

Leafless

Dichotomously

branched

Fertile appendage

Stem of Psilotum nudum

enation“Synangium”

Fused

sporangia

triloculed

Bifid sterile

aparatus

Important characteristics of

Whiskferns

• Homosporous

• Has bisexual gametophytes

• Vascularized gametophytes and rely on

mutualistic fungi for nutrition (mycorrhizae)

Phylum Lycophyta

• Commonly called clubmoss

• Leaves called “microphylls”

• Homosporopus and heterosporous groups

• First to have true roots

Taxonomic Classification

Phylum Lycophyta

Class Lycopsida

Order Lycopodiales

Family Lycopodiaceae

Genus Lycopodium

Order Selaginellales

Family Selaginellaceae

Genus Selaginella

Lycopods alive today are small - all

have lycophylls (1 vein, intercalary

meristem)

Extinct Lycopods were tall trees:

make up some of coal deposits

Lepidodendron

Cones or strobius –

aggregates of

sporophylls

Photosynthetic

stem

Dichotomous

branching

Lycopodium digitatum

Absence of

leaf gaps

Stem is

covered with

microphylls

Isophyllous –

with one type

of leaves

Lycopodium squarrosum

Strobilus- reproductive structure

contains sporangia and spores

Cones or strobilus – with leaves called sporophylls

which bear sporangia

Sporophylls- specialized leaves of sporophylls

Selaginella- heterosporous

lycopods

Selaginella bigelovii

Selaginella bigelovii – “resurrection

plant”

Selaginella cinerascens –

“spikemoss”

Some Lycopods have dimorphic leaves

Two large

lateral leaves

and two small

inner leaves

Heterospory in Selaginella – formation of

megaspores and microspores

Difference between Lycopodium and Selaginella

Lycopodium

isophyllous

Homosporous

Without rhizophore

Monoecious

gametophytes

Selaginella

leaf dimorphism

Heterosporous

With rhizophore

Dioecious

gametophytes

Lycopods native to San Diego area:

Isoetes - Merlin’s Grass

Taxonomic Classification

Phylum Lycophyta

Class lycopsida

Order Isoetales

Family Isoetaceae

Genus Isoetes

Isoetes – “Quillworts”

Aquatic lycopods

With corm-like

stem

Quill-like leaves

CAM metabolism

Isoetes

Corm –

underground stem

Quill-like leaves

Phylum Equisetophyta

• Equisetophytes (Equisetum) - Scouring Rushes /

Horsetails

• Have ridged stems

• Whorled microphylls

• Silica in cell walls

Taxonomic Classification

Phylum Sphenophyta/Equisetophyta

Class Sphenopsida

Order Equisetales

Family Equisetaceae

Genus Equisetum

rammossissimum

arvense

Equisetum hyemale

Common Scouring-Rush

Ridges and elevations

on the jointed stems

Nodes and internodes

Nodes- with megaphylls

in whorled phyllotaxy

Equisetum laevigatum

Smooth Scouring-Rush

Cone or strobilus

Equisetum arvense Common

Horsetail “dutchman’s pipe”

Ridged stem of horsetail

Phylum Pterophyta - Ferns

Parts of sporophyte

• 1. rhizome

• 2. roots

• 3. leaves called “fronds” – simple,

compound

4. erect stem is called caudex

5. fiddle head – young fern leaf

Leaf called frond – segment is

called pinna or leaflet

Pinna or

leaflet

showing

sori

Fiddle head – young fern leaf

Growth pattern is

called “circinnate

vernation”

sorus

-group of leptosporangia

Two types of ferns according to

sporangial development

• Leptosporangiate – sporangia develop

from a single initial cell

Order Filicales and others

• Eusporangiate – sporangia developed

from a group of meristematic initial cells

Order Ophioglossales

Order Marattiales

Sorus covered with indusium –

“indusiate”

Sorus- cluster of sporangia

Leptosporangiate Ferns

Leptosporangium:

one cell thick

spores ejected

sporophyte(2n)

gametophyte(n)

youngsporophyte(2n)

sperm cell(n)

egg cell(n)

archegonium

antheridium

spore(n)

rhizomesori

leptosporangium

gametophyte(n)

annulus

spores(n)

Gametophyte –

chordate and

photosynthetic

Antheridium- sperm cells

Archegonium – egg cell

Lygodium

Climbing Fern - a vine

Cyathium

a tree fern

Giant skycraper

– with erect stem

called caudex

Used for orchid

post

Adiantum reniformis

California Maidenhair Fern

Platycerium Staghorn Fern

Aquatic ferns

MarsileaSalvinia Azolla

Azolla Mosquito Fern

• - symbiotic

relationship with blue

green bacteria

• - “seeded” in rice

paddies for nitrogen

fixation