PRIMITIVE VASCULAR PLANTS

Ferns and Fern Allies

Adaptations to life on land

vascular tissue – specialized tissues for transport

xylem – e.g. tracheid Tracheophytaphloem

complex organization – possess true plant organs (basic structure and function)

rootstemleaf (cuticle)

alternation of generations – sporophyte dominant (gametophyte independent in primitive forms, dependent on s’phyte in advanced forms)

embryophyte condition – gametes and embryo protected (no need for env’l

water)

Psilophytes (Whisk Ferns)

whisk ferns first vascular plants (earliest to evolve accdg to

the fossil record extinct or not extinct)no specialized organs no differentiation

between root and shootsmall and creepingsporophyll specialized leaves containing

sporangiamotile sperm swims in water e.g. Psilotum

Lycophytes (Club Mosses)

club mosses true roots, stems and leaves (small and scale-

like, arranged spirally)sporophyll specialized leaves containing

sporangiawater required for reproductione.g. Lycopodium (ground pine)

Selaginella

Sphenophytes (Horse Tails)

horsetails leaves arranged in whorls (small & simple) on

the stem (siliceous)motile sperm must swim in watere.g. Equisetum (scouring rush)

Pterophytes (Ferns)

vascular tissue well-developed w/ xylem & phloem

thrive in predominantly damp or seasonally wet habitats

sporophyte dominant, gametophyte inconspicuous

structure of the sporophyte:

leafy frond bearing sori (sorus) ctg. spores

fiddlehead with circinate vernation

rhizome (underground stem)structure of the gametophyte

heart-shaped prothallusrhizoidsantheridia & archegonia reproduction

requires watere.g. Pteris, Adiantum, Christella