BIOL 2P93 Lecture 28: 28. Angiosperms – Evolution pt 2
24 Jan 2016
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Order austrobaileyales: 3 families of flowering plants: austrobaileyaceae, schisandraceae. 100 species of woody trees, shrubs/liana (long stemmed woody vine); lives in moist, tropical forest understories, adapted to low light. Large flowers show many features what ancient bisexual flowers may looked like. Outer floral whorl has spirally arranged tepals, next whorl have of spirally arranged stamens w/ yellow anthers supported by flattened tructures than filaments. Stamens move spirally toward flower center becomes more sterile, losing anthers + making novel whorl btwn stamens + carpels. Purple spotted staminodes isolate pollen- bearing stamens from carpel tips in flower center. Austrobaileya scandens: flower was photographed in wet tropics of north east queensland, australia. Mesangiospermae (rest of angiosperms) clades: ceratophyllales, chloranthales, eudicots, Suggested magnoliids first clade to diverge from ancestral angiosperm. Magnoliidae (magnolids): 9,000 species of flowering plants: magnolias, nutmeg, bay laurel, Has trimerous (3 sepals, petals + stamens) flowers, pollen w/ 1 pore + branching veined leaves.
