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Chapter 22 (Archaeopteridales (trees that were 8.4 meters tall, abundant…

- - - - on short axis
      - this is compared to sporophylls
      - axillary bud
        
        microscopic
        
        megasporophylls are fused laterally forming
        
        ovuliferous scale
    - - a zygote does not immediately form from an embryo in conifers: instead ....
        
        some of the cells elongate as a suspensor that pushes the other cells deep into the megagametophyte
        
        these other cells called the pro embryo develop into the embryo
        
        no doubly fertilization as occurs in angiosperms rather the female gametophyte continues to grow and acts a haploid nutritive tissue similar to endosperm
- - - - developed megaphyllous leaves
      - evolution of vascular cambian
    - - wood was almost indistinguishable from that of many living conifers
      - contained elongated tracheas most with circular bordered pits
      - little or no axial parenchyma
      - rays were all and univariate and consisted of procumbent ray tracheids
- - - - cycadophyta-cycads, extant
      - Pteridospermophyta; seed ferns all extinct
        
        upper Devonian period
        
        form a grade rather than a clade
        
        any woody plant with fern-like foliage that bore seeds instead of sori (clusters of sporangia) on its leaves
        
        resembles modern tree ferns , except they had wood and others were vines
        
        long lived vascular cambium
        
        ring of vascular bundles surrounding a pith an arrangement that also occurs
        
        seed ferns were manoxylic much softer and less dense than wood conifers and progymnosperms
      - Cycadeoidophyta; cycadeoids all extinct