Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapter 21 (Ferns (leptosporangiate fern trees (everyday familiar fern),…

- - - - transformation hypothesis
        
        postulates that after the dibiontic life cycle originated both gametophyte and sporophyte became larger more complex and vascualized
- - - - single main trunk rather than a series od dichotomies
- - - - large enations 4 cm long
      - single well developed trace of vascular tissue
      - long enations helped with photosynthesis
        
        could be called leaves
    - - also called lycophyta
      - true roots that allowed lycophyte sporophytes to anchor firmly absorb efficiently and thus to grow to tremendous size
- - - - homosporous there were no separate microspores and megaspores
- - - - protaoxylem with no pith this is a located in the center and metaxylem differentiates on the outer edge of the xylem mass
      - protaoxylem is the xylem that differentiates while cells are small and narrow and
      - metaxylem differentiates after the cells have expanded for a few more days, and are larger
      - exarch protostele
        
        present in early vascular plants
      - siphonostele
        
        pith is present in the center as occurs in the stems of ferns and
- - - - approximately 200 living species with prostrate rhizomes that have true roots and short upright branches
        
        spores germinate and grow into bisexual gametophytes that produce both antheridia and archegonia
      - selaginella is less common in temperate north america and its plants are smaller and easily overlooked or mistaken to be mosses
        
        best known species is the resurrection plant
      - selaginellas can be distinguished from lycopodiums by a small flap of tissue the ligule
      - stylites are similar to isoetes