Found Plants' roots pushed back after posting the Beeb article.

The journal Nature rarely disappoints.

Plants' roots pushed back
10 August 2001
JOHN WHITFIELD

'... Fungi made landfall about 1.5 billion years ago, followed by plants about 800 million years later, conclude Blair Hedges and his colleagues at Pennsylvania State University from a comparison of the organisms' proteins1.

By removing carbon dioxide from the atmosphere, plants might have given rise to 'Snowball Earth', when glaciers covered the planet 700 million years ago. And by releasing oxygen, plants could have detonated the Cambrian explosion of 550 million years ago, when the major animal groups evolved over 5-10 million years....'