Out at the Basaltic Mounds last Monday, I came across a lichen that got me pretty excited. It is the only macrolichen I have yet to find in the mima mounds areas, and after staring at micro-lichen so much recently (crustose), I was so happy to find it, especially as a huge patch. The patch was at least one meter square patch, an area composed primarily of bare soil and fist sized basaltic rocks, and located in the area between the basaltic mima mounds (inter-mound area).
This foliose lichen was pretty well attached to the soil in certain parts, rhizines had dug into the soil, and they were not attached to rock. So I picked one up and brought it to the lab. After microscope work, chemical work, and using three different keys to ensure accuracy, I figured it out: Xanthoparmelia wyomingica. Although my collaborator Jessica Allen already added this species to the inventory list last year, identifying this species was really fun because it brought back a flood of memories. I remember helping her key it out while we were in Bruce McCune’s lab at Oregon State University, checking the identification with McCune’s extensive lichen specimen collection, and having McCune verify the ID. All very exciting. Jessica is the person who got me into lichen – before I met her I was all about fungi!
But, back to Xanthoparmelia wyominca — how do you know if you find it? Well, they grow on the top of soil, sometimes they detach from the soil and wander around and you’ll find one of them caught in the base of a shrub – a vagrant lichen these are called, but they are not the typical vagrant lichen like Xanthoparmelia chlorochroa.
Typical vagrant lichen will roll their margins when they dry up, this allows the photobiont (algae) to be protected from the sun. When suitable moisture occurs the margins will unroll, allowing the photobiont to receive light and photosynthesize. But X. wyomingca doesn’t curl in its margins as extensively as X. chlorochroa. So look for that.
Also check the underside for color: blackish. The lobes will be pretty skinny along their length, less than 2mm, though they’ll be wider at the end and at the point where the lobe branches at the base. And especially check for the presence of rhizines – these rhizines are black, numerous, and 0.5-1.0 cm long and they are unbranched for the most part, although some seem to fuse together at the base and appear forked.
Also check for the photobiont, in this case it is green. And always do your chemical tests! And last but not least – take pictures of the process, take notes, and then put them up on Mushroom Observer so you can get feedback and make sure that your identification is correct!
Recent research published last year indicates that the genus Xanthoparmelia is polyphyletic, meaning they do not come from the same ancestor and subsequently should not be part of the same genus classification. Additionally, the genetic testing of 18 different species found 21 species clusters, however these clusters do not neatly overlap with the 18 species groups, which has provocative implications. The current species groupings are based on morphological traits and chemical composition, and assumes that species that have similar features should be grouped together phylogenetically (on the same tiny branch of the tree of life). The genetic data indicates that this assumption is false, that many of the traits were developed independently of each other (convergent evolution), and that there is a high level of variation of these traits within individuals of this species (S.D. Leavitt et al. 2011).
“Species delimitation in taxonomically difficult lichen-forming fungi: an example from morphologically and chemically diverse Xanthoparmelia (Parmeliaceae) in North America.” By S.D. Leavitt, L.A. Johnson, T. Goward, and L.L. St. Clair in Molecular Phylogenetics and Evolution. September 2011.
“A Key to Xanthoparmelia in North America, Extracted from the World Keys of Hale 1990″ by John W. Thomson in The Bryologist 1993.