Palæos: Plants		Spermatopsida
SPERMATOPSIDA		Spermatopsida

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Spermatopsida: Seed Plants

LIFE 
|--Eubacteria
`--Eukarya
   |--+--Rhodophyta
   |  `--Chlorobionta 
   |     |--Lycophyta
   |     `--Spermatopsida
   `--+--Fungi
      `--Metazoa
         |--Chordata
         `--Protostomia

Araucaria sp.

The evolution of seeds represents one of the most important events in the evolution of vascular plants.   Seeds are actually embryonic plants contained within hard coats that protect the embryo against harsh environmental conditions (dessication etc).  The embryonic plant is given nourishment that will aid it in it's new beginning, like the yolk of an egg. Seeds can be dispersed long distances and can remain viable for long periods of time. Then when the right conditions come along  the seed germinates and produces a new plant.

<==o SPERMATOPSIDA 
   |-- †Calamopityaceae
   |-- †Hydraspermaceae
   `--+-- †Lyginopteridaceae
      `--+-- †Medullosaceae
         `--+-- †Caytoniaceae
            |-- †Corystospermaceae
            |-- †Peltaspermaceae
            |-- †Gigantonomiaceae
            |-- †Czekanowskiaceae
            |--o †CALLISTOPHYTALES
            |  `-- †Callistophytaceae
            |--o †GLOSSOPTERIDOPHYTA
            |  `-- †Glossopteridaceae (glossopterids)
            |--o CYCADALES [Cycadophyta] (cycads)
            |  `-- Cycadaceae
            |--o GINKGOALES (ginkgos)
            |  `--o Ginkoaceae (ginkgos)
            |     `--o Ginkgo
            |        |-- †G. adiantoides
            |        `-- G. biloba 
            |-- CONIFEROPHYTA (conifer-like plants)
            `--o GNETICEA [Chlamydospermopsida]
               |-- †PENTOXYLALES
               |-- †CYCADEOIDALES [Bennettitales] (cycadeloids)
               |--o GNETALES
               |  |--o Ephedraceae
               |  |  `-- Ephedra
               |  `--+--o Welwitschiaceae
               |     |  `-- Welwitschia
               |     `--o Gnetaceae
               |        `-- Gnetum
               `-- ANGIOSPERMOPHYTINA [Magnoliophyta]

Crane, P., 1996-1999: Spermatopsida - Seed Plants. --iNet: The Tree of Life

Donoghue, M. J., 1996-1998: Gnetales. --iNet: The Tree of Life

Parker, Sybil P. (ed.), 1982: Synopsis and Classification of Living Organisms. New York: McGraw-Hill Book Co., 2 vols.