Flowering Plant Families

Monocot and Eudicot families

The first flowering plants (Angiosperms) appeared 150 to 190 million years ago.They then rapidly diversified during the early Cretaceous period (145 to 66 Ma) and outcompeted the previously dominant ferns and conifers. They split into 2 major groups over 100 million years ago – the Monocotyledons (Monocots) and the Dicotyledons (Eudicots). Current estimates are that there are 413 Families of which 106 are Monocot families and 307 are Eudicot Families.

Monocotyledons (Monocots) germinate with one cotyledon (the first ‘seed leaf’ produced by the embryo, which may appear above ground or remain below), can’t form wood and have parallel leaf venation.  They include orchids (20,000 species), grasses, food forms such as asparagus, onions and garlics, horticultural plants such as lilies, daffodils, irises, amaryllis, alliums, agapanthus, bluebells and tulips and some tree forms such as Palms. 

Flower parts usually in multiples of three so  the Lily shown below has 6 white tepals and 6 red anthers.

Monocots are a clade (i.e. have a common ancestor) and include 60,000 species in 77 families.

Leaf veins are usually parallel

monocotyledon leaf veins

Eudicots, formerly called Dicotyledons germinate with two seed leaves and can form wood or be herbaceous.  Historically there were only Monocotyledons and Dicotyledons but then it was discovered that a minority of dicots did not evolve from the same ancestors. The large subgroup of dicots were then named Eudicots – all came from the same ancestor and had the same pollen structure – 3 grooves on the pollen grain called tricolpate. The term Dicotyledon should no longer be used. The minority of dicotyledons with 1 groove on their pollen grains are known as Magnoliids.

Flower parts usually in multiples of fours or fives. 70% of all Eudicot species are pentameric ( flower parts in fives).

This group makes up 75% of all flowering plants.   Eudicots include 190,000 species in 311 families.

Leaf veins are usually netlike