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