How the First Plant Came to Be

Earth is the planet of the plants–and it all can be traced back to one green cell. The world's lush profusion of photosynthesizers–from towering redwoods to ubiquitous diatoms–owe their existence to a tiny alga eons ago that swallowed a cyanobacteria and turned it into an internal solar power plant. [More]

Read more here:
How the First Plant Came to Be