In the Race to Live on Land, Lichens Didn’t Beat Plants

A study’s findings add to the case that lichens, which dominate about 7 percent of the planet’s surface, most likely made their way to land some 100 million years after ferns and other vascular plants.

Crustose Ophioparma lichen. There are 13,500 species of lichen and they dominate 7 percent of the Earth’s surface. Matthew P. Nelsen, Field Museum

By JoAnna Klein

19, 2019Updated 2:54 p.m. ET

A lichen is what happens when a fungus hugs an algae and doesn’t let go. It’s a sweet arrangement: The fungus offers shelter, and algae feed the fungus. They’re still separate species, but tear them apart and the fungi typically can’t survive. So they’ve long been studied as a single organism…