Phylogeny

Earliest flowering plants
Charles Darwin referred to the sudden appearance of angiosperms in the fossil record as “an abominable mystery”
Where did angiosperms come from?
What were the earliest flowering plants like?
How did they give rise to the diversity we see today?
Jurassic Park
Age of Dinosaurs was also age of ferns and gymnosperms
Vascular plants present in the fossil record 400 million years ago
First seed plants about 300 million years ago (seed ferns)
200 million year old fossils show some flower-like features, but not quite there
First fossil flowers about 130 million years old
Plants do not preserve well, so our fossil record is very spotty.

Early relative of magnolia
Well-preserved fossil flower
Characteristics of a primitive flower
Flower parts:
Indefinite number
Spiral arrangement
Numerous
Parts free (unfused)
Petals
Sepals
Carpels
Stamens

Characteristics of a primitive flower
Bisexual
If unisexual, plant monoecious
Actinomorphic
Hypogeny
Solitary
Complete

Primitive vegetative characters
Woody
Perennial
Leaves persistent
Venation reticulate
Chlorophyll present
Advanced flower characters
Flower parts:
Definite number
Cyclic arrangement
Few
Advanced flower characters
Parts united (fused)
Petals
Sepals
Carpels
Stamens

Advanced flower characters
Imperfect
Dioecious
Zygomorphic

Advanced flower characters
Epigyny or perigyny
Inflorescence
Petals absent

Advanced vegetative characters
Herbaceous
Annual
Leaves deciduous
Venation parallel
Chlorophyll absent
Primitive or advanced?
Trends
Primitive:
Flowers with few to many parts that are indefinite in number.
Floral whorls four: sepals, petals, stamens, pistils, all spirally attached on an elongated axis.
Ovary superior
Actinomorphy
Advanced:
Flowers with few parts that are definite in number.
Floral whorls 3, 2, or 1, axis shortened, parts not apparently spiral.
Ovary inferior
Zygomorphy