Marchantia Alpestris - A Liverwort

Day 269: By and large, liverworts are far less common than mosses and lichens, and thallose liverworts (those having a "leafy" structure) even less common. In fact, most of our local species closely resemble mosses, so separating them visually without a hand lens can be daunting. On the other hand, the thallose species sometimes look like lichens, and that factor was what drew my attention to this specimen. From a distance, I took it to be Peltigera venosa, but on closer inspection, the pores and gemma cups characteristic of Marchantia became obvious. Although difficult to see in this photo, just above center in the middle of the lobe and again in the center of the lobe to the left, these structures are evident, each cup containing several gemmae (the spore-bearing "eggs" of the species). "Liverwort!" I exulted to my botany partners, Joe and Sharon. "But that's as far as I'm willing to go."

At home, I turned to the only two field guides covering Pacific Northwest liverworts to any extent, certain that they'd be inadequate to the task. I got as far as genus: Marchantia. My specimen was considerably larger than Marchantia polymorpha (a common pest in greenhouses, and one of very few liverworts I can recognize in the field), so I referred it out to expert David Wagner, who identified it as Marchantia alpestris, a species which occurs at higher elevations.

Asterella Gracilis, Syn. Mannia Gracilis

Day 243: "Minions." That's what Joe thought they looked like. At first glance, I thought they were an odd seed head, but rejected that idea after ascertaining that the adjacent foliage did not belong to the same plant. With my nose only an inch from the rock, I began a search for clues. If you'd been in the area, you'd have heard my whoop of exultation echo off the canyon walls when I found the answer. "It's a LIVERWORT!" At the moment, I had to be content with that alone.

Upon consulting field guides at home, I determined it belonged to the Asterella genus. I suspected it of being A. gracilis, but I had no way to confirm that simply from photos. Another trip was made to obtain a specimen even though I knew I was in over my head. One of my lichenology contacts referred me to liverwort expert David Wagner of the Northwest Botanical Institute in Eugene OR. After obtaining permission from the Park's Plant Ecologist to refer the specimen out for analysis, I mailed it to David. When I got home from work last night, his reply was in my email: "I have received the capsules and the spores show this is Asterella gracilis. Its reddish coloration on the carpocephala is not typical and the spores are a pale brown rather than yellow but otherwise it has typical ornamentation. The purple scale appendages at the tip of the thalli is also typical."

He went on further to explain that in 2010, A. gracilis was proven to be more closely related to Mannia than to other Asterella species and therefore could be called Mannia gracilis "if one wishes to ignore morphology in favor of DNA analysis," a statement which goes to show that I'm not the only one who has trouble accepting taxonomic shifts. Still, I couldn't be happier if Santa Claus had showed up on my roof with all the Christmas presents on my list.