Usnea Filipendula

Day 28: I've often said that if you hold still more than five minutes in the Pacific Northwest, you're likely to be colonized by lichens or moss. The trees in my yard host a variety of species and I'll admit it: I haven't identified them all. The Usneas are particularly difficult, so I set myself a microscope exercise for the morning and after close study of this specimen from the pussywillow's branches, determined that it is U. filipendula. This uncommon species is characterized by round branches which are not cigar-shaped, bearing tall papillae (small bumps) and tuberculate soralia (raised openings in the cortex). Annular cracks are inconspicuous, although the microscope reveals them near the bases of the fibrils. Had you observed this lichen a month ago, you would have found that it was stiff and dry. Rain and cool temperatures have returned it to a soft and pliable state. Lichens are remarkable in their ability to survive with very little available moisture, and like this Usnea, they hold onto whatever they can get.

Relearning Curve

Day 113: My "relearning curve" has flatlined when it comes to this beautifully lush Usnea. Once known as Usnea dasopoga, it was frequently misspelled by amateurs and academics alike as "dasypoga," and was eventually renamed Usnea filipendula. Like many other things in botany, it has had a wealth of other synonyms attached to it over the years, but fairly recently, its name has reverted to the original. Do you think I can remember "Usnea dasopoga" when the need arises? Not hardly! I persist in calling it "filipendula," preferring the euphony of the word. The retired term is particularly descriptive; "filum" also gives us the English "filament,"and "pendulus" means "hanging." Indeed, Usnea fi...(dammit)...appears as a graceful mass of hanging threads, especially when hosted on its favourite medium, spruce. As for "dasopoga" or its misspelling, I can find no etymology, none whatsoever. It seems to be a nonsense word, the creation of a taxonomist who was too deeply in his cups, armed dangerously with a load of Scrabble tiles. Without roots to support it, "dasopoga" refuses to grow in my mental garden.

Snow For Christmas

Day 72: Random musings, here. I am staying home for Christmas this year, fixing myself a turkey and stuffing, snuggling down with the cats, sharing gift-giving with my sisters-of-the-heart, and in a way, it feels more "Christmas-y" than it's felt in years. This sense is augmented by the fact that there is snow on the ground and more falling at this very moment, maybe not a Currier and Ives scene yet, but at least Bing Crosby wouldn't be disappointed. I think I'm "lichen" being home alone, watching the little birds flit in and out of the feeders, listening to their happy chatter. I'm warm, there are bright lights on the tree, and the spirit of Love announced itself with a firm bite on the back of my arm to let me know I should put aside the quilting to provide Skunk with access to a comfortable lap. She's an old lady. It takes her ten minutes to figure out how to arrange her bones. Maybe I took a lesson from her: find a soft spot and make the most of it. Cats are wise people, wiser far than humans.

Identifying Usnea

Day 38: One of my favourite tools for introducing beginners to lichen identification is provided by the family of Usneas: a stretchy "rubber band" or "spinal cord" which reveals itself when a section of the lichen is stretched gently to open the cortex. Even the tiniest branches possess this elastic core (note upper arrow in the microscope view), but of course they're thicker in the main branches.

A couple of years ago, I had occasion to take a troop of Scouts on a lichen walk in Longmire Campground where Alectoria (a different family) is present in abundance. I explained how to differentiate it from the Usneas and unbeknownst to me at the time, one of the boys took it as a challenge. As we progressed around the campground, he kept picking up bits and stretching them. After what must have been a few hundred tests, he came rushing up to me in excitement. "Crow! Crow! I found an Usnea!" Sure enough, as he carefully stretched the section, the "spinal cord" was revealed. His diligent pursuit of the elusive lichen had paid off, and I knew in that moment that I'd inspired the spirit of scientific curiosity in that young man. When I'm down and feel that nothing I do matters, I try to remember those occasions when my labours paid off. Damn, but I was proud of that kid!

Comparative Lichenology

Day 41: East meets West for today's essay! A friend recently sent me two lichen specimens from Maine in the hopes that I could identify them for her. One of them was a member of the generic category of "Old Man's Beard lichens," specifically Usnea filipendula (Fishbone Beard, top photos). It put me in mind of my favourite among the Usneas, Methuselah's Beard (U. longissima, lower photos), so I thought it would be fun to present them paired, and thus took a short hike to a location where longissima is abundant.

As you can see, Fishbone is much more compact and delicate. Longissima grows in graceful strands up to ten feet in length. Filipendula branches abundantly, and Methuselah's Beard consists of threads on a central stem, much like a Christmas garland. A microscopic view reveals that isidia (grain-like reproductive units which detach easily from the thallus) are present on both specimens, but are more numerous in the case of filipendula. Both species are excellent air-quality indicators. Sensitive to even small amounts of pollution, Usneas only grow where the air is pure.