Lobaria Pulmonaria, Apothecia And Soralia

Day 96: The specialized vocabulary of lichens can be daunting even with a glossary in hand. Let's talk about two types of reproductive structures as they appear on Lobaria pulmonaria (Lung Lichen). The first is "apothecium" (plural, apothecia), visible here as raised brown discs. These are fruiting bodies, i.e., they bear spores which allow the lichen to reproduce sexually with spores from another lichen. However, many lichens are capable of asexual reproduction as well. Lobaria pulmonaria is a case in point. Asexual reproduction occurs when it generates miniature clones of itself. These genetically identical offspring are called soredia (singular, soredium) and emerge through the cortex of the lichen in soralia (singular, soralium), visible in the photo as small white ring-shaped dots. Soralia may appear along the margins of L. pulmonaria's lobes as well, and often in great abundance. A similar lichen, L. linita, may be found in the same environment, however, it does not produce soralia.

Happy As A Wet Lichen

Day 24: You've heard the phrase, "mad as a wet hen." How about "happy as a wet lichen?" Lichens have a variety of strategies for gathering moisture, and can survive for protracted periods of dry weather by being able to maximize what little is available as dew and in the form of humidity. Many lichens have rough or scaly cortices which increase their surface area substantially. Others like Lettuce Lung (Lobaria pulmonaria) have dimpled foliage in which water pools and is subsequently absorbed into their tissues. Had you seen this specimen in late summer, you would have thought it was dead. The lobes were brown and so crisp that they could easily be crumbled between probing fingers. However, once the autumn rains began, this lichen quickly came back to life and greenness.

Green Grow The Lichens

Day 20: Some years ago, a pussywillow twig I had cut to bring indoors sprouted roots in the vase. I planted it at the corner of my garage where it became a tree within a relatively few years. However, it was not particularly happy. The soil there is fill, and poor fill at that, rife with bits of broken glass, fragments of rusty cans and, I suspect, chemicals I'd rather not think about, courtesy of the previous owners. The pussywillow tried its hardest, but to add insult to injury, it was then attacked by insects which in turn were harvested by a determined Sapsucker who drilled and shredded the bark until the main trunk died. That said, the weakened wood was primed for lichen colonization, first by Parmelias and Usneas, and now by these young Lobarias. People think lichens damage trees. In fact, they have the process backwards. Lichens take advantage of the softer, more porous wood and bark of sick and failing trees, and do not contribute substantially to the trees' eventual demise. Is my pussywillow doomed? I don't think so. Willows are remarkably resilient, and as long as the root is undamaged, new shoots will no doubt spring up. And if not, a twig from this tree also sprouted roots, and I planted it in the front yard where it's doing just fine.

Wet And Dry

Day 139: These two photos were taken only three days apart, and they point up one of the issues lichenologists have to face when they're trying to make an identification. A specimen can look very different depending on whether it's wet or dry. Lobaria pulmonaria (Lung Lichen), a common species on Mount Rainier National Park's wet west side, is known for its bright green colour and the ridges which texture its lobes. However, when it dries out, it appears almost grey. A rain shower is all it needs to perk it back up, though. Moisture settles into the network on its upper surface and quickly revitalizes the algae which provide its distinctive hue.

Lettuce Lung, Lobaria Pulmonaria

Day 159: What urged me to walk back to the site of yesterday's froggy encounter was this specimen of Lettuce Lung (Lobaria pulmonaria) on which the seldom-seen brown apothecia (fruiting bodies) were clearly apparent. Although the lichen is abundant in this area, I observed apothecia only on this one example. Lettuce Lung prefers old-growth forest and is sensitive to atmospheric pollutants, so if you happen to find yourself where it grows, you may be assured that you're breathing clean air.