Classification of pteridophyta

Classification of

pteridophytes

For a long time the division Pteridophyta included-the ferns

lycopods and horsetails On the basis of their anatomy Jeffrey in

1902 divided the vascular plants into two types or lsquostocksrsquo He

included

bull ferns gymnosperms and angiosperms in a lsquostockrsquo known as

Pteropsida

bull lycopods and horsetails in another lsquostockrsquo known as Lycopsida

Scott in 1923 ranked them as divisions He segregated the

horsetails as a separate division the Sphenopsida

According to Eames (1936) Tippo (1942) and others there is

a single division the Trachaeophyta consisting of four subdivisions

1 Psilopsida

2 Lycopsida

3 Sphenopsida

4 Pteropsida

Classified into 4 divisions that have 40 families They include

about 10000 living species (365 genera) distributed worldwide

Classes of pteridophytes

1 Psilophyta 2 Lycophyta

3 Sphenophyta

4 Pterophyta

Sub classes

Division I Psilophyta Class 1 Psilotopsida

Division II Lycophyta

Class 1 Ligulopsida

Class 2 Eligulopsida

Division III Arthrophyta

Class 1 Sphenophyllopsida

Class 2 Calamopsida

Division IV Filicophyta

Class 1 Primofilicopsida

Class 2 Eusporangiopsida

Class 3 Protoleptosporangiopsida

Class 4 Leptoprotosporangiopsida

1 Psilophyta(Whisk ferns)

Two genera (Psilotum and Tmesipteris) and 4-8 speciesbull Most primitivebull Rootless with rhizoidsbull Leaves often absent

bull Dichotomously branched photosynthetic stembull Protostele is the condition where central core of xylem surrounded by phloembull Homosporous Synangium trilocular structure that encloses sporangiabull Eg Fossil genera Rhynia and Horneophytonbull Living genera Psilotum and Tmesipteris


2 Lycophyta (Club moss or spike

moss)

bull Differentiated plant bodybull Microphyllous leavesbull Protostele sometimes siphonostelebull Sporophylls aggregate to form strobili or conesbull Both homosporous and heterosporous Lycopodium is homosporous whereas Selaginella is heterosporousbull Gametophyte depends on fungus for food


moss)

3 Sphenophyta (Horse tail)

A single genus which have 35 species

bull All are fossils except Equisetum

bull Differentiated plant body

bull Stem joined with nodes and internodes

bull Scaly leaves seen as whorl around the node

bull Sporangia forming strobilus or cones

bull Homosporous


4 Pterophya (Ferns or

Filicophyta)

bull Most widely distributed vascular cryptogamsbull Differentiated plant body stem mostly rhizomatousbull Leaves macro phyllous called as frondsbull Young leaves show circinate vernation (spirally coiled)bull Stele protostele siphonostele or dictyostelebull Sporangia form sori on abaxial side of the leafbull Sporocarp in Marseliabull Indusium may be true or falsebull Homosporous (Pteris) or heterosporous(Marselia)bull Antherozoids multiflagellated


Filicophyta)

Classes of pteridophytes

1 Psilophyta 2 Lycophyta

3 Sphenophyta

4 Pterophyta

Sub classes



Class 1 Ligulopsida




Class 2 Calamopsida











moss)



moss)








bull Homosporous



Filicophyta)



Filicophyta)

Sub classes



Class 1 Ligulopsida




Class 2 Calamopsida











moss)



moss)








bull Homosporous



Filicophyta)



Filicophyta)






moss)



moss)








bull Homosporous



Filicophyta)



Filicophyta)



moss)



moss)








bull Homosporous



Filicophyta)



Filicophyta)


moss)



moss)








bull Homosporous



Filicophyta)



Filicophyta)


moss)








bull Homosporous



Filicophyta)



Filicophyta)








bull Homosporous



Filicophyta)



Filicophyta)



Filicophyta)



Filicophyta)


Filicophyta)



Filicophyta)


Filicophyta)

Science

Classification of pteridophyta