Xanthoria Polycarpa On My Beat

Day 311: Recently, I gave a talk to a group of Park volunteers which was primarily focused on lichen species. The first half was conducted indoors and a field trip through Longmire Campground was scheduled for the second half. The field-trip hour turned into two and a half as I conducted part of the group through a more extensive exploration as their enthusiasm gave me the opportunity to talk about one of my favourite subjects. With some adaptations, I will be using the same lecture material for a Nisqually Land Trust talk in a few weeks, but since the Pacific Northwest will soon be entering its autumn weather pattern (read, "rain"), I'm planning an indoor "field trip" for the attendees. To that end, I want to gather specimens of a dozen or so of our most common lichen genera to have available for "hands-on," and one species which I most wanted to demonstrate was Xanthoria polycarpa, so showy with its bright orange colour. That presented a small problem: the only place I knew where I could collect a sample without spending a lot of time driving was behind the gate to a closed community where a friend used to live (and no, I don't know any of her former neighbours). I was about to despair of finding it in a more accessible location when lo and behold, there it was, growing on an ancient Oregon Ash beside one of the waypoints for my Land Trust "Forest Succession" talk, right on my very own beat, and I'd never noticed it before. Maybe I'd been too focused on the Poison Hemlock nearby. Funny how a little thing like that can distract you.

Xanthoria Polycarpa Unhomed

Day 185: This comes under the category of Great Sadnesses. I didn't know I had Xanthoria polycarpa growing on the hawthorn tree when I asked Joe to take it out, although it probably wouldn't have changed my decision to remove it. I'd planted the hawthorn when I first moved in here, asked by the friend who provided it if I was really sure I wanted one but not understanding her concern. It was only later that I found out how invasive the damn things can be, but by then, the tree was fifteen feet tall with several trunks as thick as my upper arm. To make matters worse, it was shading out one end of my grapevine. Joe said he was willing to take it down, and to that end, showed up yesterday morning with his chainsaw. As you know from my previous post, most of the morning and early afternoon were spent enlarging my garden space. It was after noon by the time we got to the tree, and both of us were experiencing the aches incumbent with hard work. Still, Joe started on the tree but the intertwined branches made for slow going. We called it quits when the job was two-thirds done. He'll be back to finish it off later (I've promised not to put him to work digging again, not this year anyway), but as we were hauling away the branches, I spotted the poor unhomed Xanthoria, collateral damage. It's not an uncommon lichen, but I love the colour. I hope the grape appreciates the sacrifice.

Xanthoria Polycarpa

Day 182: Well, fooey. I was in fairly close proximity to Puget Sound yesterday and happened across a dozen or so landscaping trees which were covered in greenish-gold lichen. Xanthoria polycarpa is common in the Pacific Northwest, but a second rarer species (Xanthoria parietina) sometimes occurs in the Willamette-Puget Trough. Knowing this, I decided to pull back into my parking space despite the rain (I'd been pulling out) and have a closer look. You never know, and if you don't check, you might miss something good. Initially, I was impressed with the size of the apothecia on this particular specimen. Then I noticed the size of the lobes. "Hmmmm," sez I. "That's bigger than any polycarpa I ever saw before." I had not brought a hand lens, nor had I brought a container, but I lifted a small sample from the bark and put it in one of the cup-holder slots in the car, reminding myself gently not to put my water bottle back in on top of it. It was the first thing I brought in the house when I got home eight hours later. This morning, I picked off one of the apothecia and did a close inspection under the dissecting scope. Nope, no rhizines at all. Hopes dashed, I was forced to rule out parietina. Drat.

Xanthoria Polycarpa

Day 188: If you have ever seen Xanthoria polycarpa (above) or its eastern cousin, X. parietina, you will never forget the colour. Seen in the distance, it assaults the eye with a statement of orange which is undeniable, but on closer observation, hints of yellow and green insert themselves into the visual perception, leaving the viewer rather in want of a proper adjective to describe the hue. To my eye, it is beautiful, arguably one of the most striking lichens in the catalog, yet I have heard more responses of "ewwwww!" to it than to any other species. Young growth or that which receives more sunlight is often a richer, orangy shade; the abundant apothecial disks exhibit strongly coloured centers surrounded by pale rims. Although this species is occasionally observed on evergreens, it prefers hardwood, here seen on the lower portion of a flowering plum which it almost entirely covered. The effect of pink flowers or mahogany leaves rising above an orange trunk is truly other-worldly!

Aptly Named "Sunburst"

Day 19: While a lot of lichens have some rather strange common names (Frog Pelt, Ticker-tape, Volcano, Deflated Tube), the logic behind "Sunburst" is obvious. Its Latin nomenclature reflects its colour and abundant apothecia: Xanthoria polycarpa, i.e., "xanthous" (yellow) and "many-fruited." It occurs farther inland than its cousin X. parietina, a species which in any event is rather rare on the west coast. Look for the apothecial disks which distinguish it from Candelariella vitellina (Common Goldspeck). Sunburst will be found on tree bark, Goldspeck almost always on rock.

Xanthoria Polycarpa, Sunburst Lichen

Day 237: Two very similar species of Xanthoria occur on the west coast of North America. Xanthoria parietina is primarily a coastal species while Xanthoria polycarpa (shown) can be found further inland. The two species can be quite difficult to differentiate when observed in the transition zone.

It is interesting to note that X. parietina is believed to have been introduced from Australia. X. polycarpa is native, and its range extends from central Alaska southward. The taxonomy is derived from the Latin "xanthus," meaning "yellow" and "polycarpus," "many-fruited" (referring to the abundant apothecial disks).

Xanthoria Polycarpa, Sunburst Lichen

Day 176: From the Latin "xanthus" meaning "yellow," the Xanthorias are a very distinctive genus of foliose lichen and, at least in the Pacific Northwest, are most commonly found growing on hardwood bark, generally in sunny, open locations. Xanthorias also colonize on rock. Their colour is striking, and often gives rise to expressions of repugnance in the uninitiated, on the order of, "Ewwww! What's that orange stuff all over the trees?" On closer examination, the structures of the lichen become apparent: a foliose thallus dotted with raised apothecial disks. Xanthoria polycarpa occurs farther inland than the very similar X. parietina, although both are primarily coastal species. X. parietina is not known to occur in Washington.