Plants spread and speciated throughout the world from the time of their terrestrial debut. Their proliferation was both of number and variety. Even the earliest forests had widely divergent plant species.
Polyploidy was the key to plant innovations. Polyploidal cells have more than 2 paired (homologous) sets of chromosomes. Whole-genome duplication afforded simultaneous gene conservation and experimentation.
Gene duplications allow evolution of genes with new functions. ~ Swedish microbiologist Joakim Näsvall et al
Gene duplication events were intensely concentrated 319 and 192 MYA. The 1st begat seed plants. The 2nd brought the proliferation of flowering plants. 90% of herbaceous plants duplicated their genomes.
At least 14,000 protein-coding genes existed in the last common ancestor of all flowering plants. Many of these genes are unique to flowering plants, and many are known to be important for producing the flower as well as other structures and other processes specific to flowering plants. ~ American botanist Joshua Der
The innovative advances in angiosperms prompted one of Earth’s greatest terrestrial radiations, famously characterized by Charles Darwin as “an abominable mystery.”