Flowering Plant - Classification

Classification

There are eight groups of living angiosperms:

• Amborella – a single species of shrub from New Caledonia
• Nymphaeales – about 80 species – water lilies and Hydatellaceae
• Austrobaileyales – about 100 species of woody plants from various parts of the world
• Chloranthales – several dozen species of aromatic plants with toothed leaves
• Magnoliidae – about 9,000 species, characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves – for example magnolias, bay laurel, and black pepper
• Monocotyledonae – about 70,000 species, characterized by trimerous flowers, a single cotyledon, pollen with one pore, and usually parallel-veined leaves – for example grasses, orchids, and palms
• Ceratophyllum – about 6 species of aquatic plants, perhaps most familiar as aquarium plants
• Eudicotyledonae – about 175,000 species, characterized by 4- or 5- merous flowers, pollen with three pores, and usually branching-veined leaves – for example sunflowers, petunia, buttercup, apples and oaks

The exact relationship between these eight groups is not yet clear, although there is agreement that the first three groups to diverge from the ancestral angiosperm were Amborellales, Nymphaeales, and Austrobaileyales. The term basal angiosperms refers to these three groups. The five other groups form the clade Mesangiospermae. The relationship between the three largest of these groups (magnoliids, monocots and eudicots) remains unclear. Some analyses make the magnoliids the first to diverge, others the monocots. Ceratophyllum seems to group with the eudicots rather than with the monocots.