Tuesday, January 23, 2007
Lobaria pulmonaria / Lungwort
Lichens have a layer of green algae under an outer skin of fungus. The internal clumps on this lichen are cyanobacteria (cephalodiums). Cyanobacteria can take nitrogen gas from the air and turn it into biologically usable compounds, so lichens with cyanobacteria can make major contributions to soil fertility. The non-sexual reproductive structures on the surface are soraliums, little balls of algae wrapped in threads of fungus (soredia) emerge from the soralium to be dispersed. Some lichens make entire non-sexual reproductive packages in the form of soredia or isidia, which are tiny projections from the surface of the lichen that can break off easily and grow into a new lichen. Most lichens are very brittle when they're dry, and some depend on just plain breakage to produce fragments that, like soredia and isidia, can be blown around by wind, washed along by water, or carried off as passengers on insects or birds. Other lichen fungi make spores to form a new lichen. These fungal spores need to capture new photosynthetic partners after they germinate. Some apparently steal them from other lichens. This lichen is used in Britain as an indicator of undisturbed ecosystems. It reminded medieval European healers of lung tissue, and they took this as a sign that it was a remedy for lung ailments. First Nations of British Columbia used it as a treatment for coughing up blood and for lung troubles. Lobaria pulmonaria was used at a Siberian monastery long ago in brewing a bitter beer.