By Jean Ponzi
Ancestor in the Driveway
“Liverworts!” cried my friend Louise, crouching over the gravel. I wish I’d had the presence of mind to grab our gardening kneel-upons, so we could have appreciated them close-up, together, right then.
Louise knows a lot about life, especially animals, and she gets excited to share. She likes plants too. Plants are my favorites. I’m always glad to learn about them and meet new ones. These tiny greenies were a big surprise.
Since that day, Liverworts have rooted in my mind. Or – correcting for their having no actual roots – they embedded their hairlike rhizoids in my imagination.
Especially having You-Tube heard about them from Robin Wall Kimmerer, who is a botanist, author, indigenous scientist, storyteller and my Green Hero. Her award-winning first book, Gathering Moss, focused on their plant group, the Bryophytes. She challenges their labelling by conventional science as primitive plants, for verbally reducing them to an inferior status.
Dr. Kimmerer honors these humble plants as Ancients.
Studies of their mitochondrial DNA say that Liverworts (phylum Marchantiophyta) were the first living beings to make the BIG leap onto land. The journal Nature reported in 1998 that Liverworts are the oldest known land plants, who began, about 476 million years ago, to transform early Earth’s toxic CO2 terrestrial soup into a literal atmosphere of life-friendly Oxygen.
BiologyDictionary.net says this drastic changing of global chemistry would later lead to “climate change and massive extinction events.” Hmm, I think, could Liverworts be OUR distant relations?
Our venerable institutionSmithsonian says, “The world of mosses, liverworts and hornworts, collectively known as bryophytes, form a beautiful miniature forest; nonetheless they are often overlooked, due to their small size and lack of colorful flowers.”
Indeed! Moss is well established along our driveway edge, but these Liverworts? No idea how long they’ve been growing in community below our cars! Given my husband’s gravel weed-pulling vigilance, it’s likely they are pretty new neighbors.
When I brought out my magnifying glass (and those foam kneel-upons) to genuinely meet them, I saw dark green, smooth surface and ruffly-edged shapes like leaves; these are called thallae. Many of these have tiny cups (gemmae) budding from their surface. Plus these totally Horton-Hears-A-Who structures, sproinging up on tiny “stems,” some resembling umbrellas (archegonia), some looking like fans (antheridia) – which are the female and male reproductive parts, respectively.
Wow! Wee worlds, spreading in a shape resembling the state of Louisiana (coincidence?) on the gravel between our pick-up truck and our car.
Like ferns, whose bio-lineage Liverworts were long thought to share, these simple plants reproduce by distributing spores. Cells and wind! The drifter romance is one of Earth’s greatest hits.
Bryophytes are non-vascular plants: no roots or water-conducting tissue. They absorb water and nutrients from the air through their leaf-like surface. Most of them are only a few centimeters high. Without roots, they can grow where other plants can’t, on the surface of rocks, walls, and pavement.
They thrive in damp, shady environments, but we find these adaptable beings in the most extreme places, from deserts to the arctic. Everywhere on Earth! Globally there are 7-8,000 species of Liverworts, about 11,000 species of their Moss relatives and 220-ish species of Hornworts.
Reading about them buzzed my brain: sporophytes and gametophytes; haploid and diploid; mitosis and meiosis. I had dodged fundamental science classes in my youth. These little lives in my driveway made me long to know more, so I nudged a cluster from their crushed-rock bed.
Liverworts are now a guest inside our home, lodged on bits of gravel in a small blue pottery bowl. With my kitchen hand lens, I’ll be spritzing, observing and learning from these place-making elders.
Liverworts, welcome to our place! Thanks, little Earth friends, for all you do.
Jean Ponzi explores Earthy topics in her Earthworms podcast conversations from KDHX.org, and through her work for the EarthWays Center of Missouri Botanical Garden.