non-seed vascular plants

• embryo
  • foot [attachment to archegonium of parent gametophyte]
  • embryonic shoot [stem]
  • embryonic leaves, or leaf primordium [in groups with leaves]
  • embryonic root [in groups with roots]
• embryo is retained in archegonium of parent gametophyte
  which supplies nutrients to developing embryo

Seeds

female gametophyte & embryo

• female gametophyte retained in megasporangium
  reduced to 1-celled multinucleate (32-1000 nuclei)structure
• embryo (2n)
  • without foot
  • with cotyledon(s) (embryonic sporophyte, 2n)
    as food storage organs
• archegonium (female gametophyte, 1n) becomes endosperm
  surrounding embryo as food storage structure
• megasporangium (parental sporophyte, 2n) forms seed coat
  forming protective layer covering seed
• seed typically becomes dormant during non-growing season
• seed germination delayed until next growing season, or longer

male gametophyte

• microspores retained in microsporangium (parental sporophyte, 2n)
• male gametophytes typically 2-celled pollen grains
  with heavy cell walls, adapted to wind dispersal
  some dispersed by animal agents [mostly insects and birds]

Cones

• microsporangia and megasporangia borne on highly modified leaves
  on compressed axis, producing compact strobili
• microsporophylls & megasporophylls typically woody bracts
• some megasporophylls fleshy berry-like structures
  borne singly on leaf rachis (often dichotemous branched once)

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