Division Magnoliophyta (Anthophyta): Flowering Plants
• Transformation of Gymnosperms to Angiosperms
– Sporophylls needed to evolve into stamens and carpels (forming
a flower)
– The most primitive angiosperms have stamen that are very flat
and the stamen lack filaments
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Division Magnoliophyta (Anthophyta): Flowering Plants
– Carpels are also very leaflike
– Evolution of double fertilization and the formation of endosperm
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Division Magnoliophyta (Anthophyta): Flowering Plants
– Evolution of vessel elements and sieve tubes
– Leaves
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Became broad
Reticulate venation
Polymorphic
Had functions other than photosynthesis
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Origin and Early Evolution of the Angiosperms
• C.E. Bessey developed a theory of evolution for
angiosperms based upon a Magnolia type flower
being the most primitive – “ranalean” flower
– Flower contains all of the floral parts
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Sepals
Petals
Stamens
Carpels
– All parts arranged spirally
– Carpels superior
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Origin and Early Evolution of the Angiosperms
– Wood very similar to that of gymnosperms
– Evolution of insect pollinators (bees, butterflies, beetles, and
flies) also occurred at the same time as the above advances
were appearing
Angiosperm evolution still a wide open question – great
opportunity for research
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