My sample was collected from a Douglas fir (Pseudotsuga menziesii), the first clue as to its identity. However, I was not certain that I was observing a secondary interior exciple ring in the well-developed disks, a feature which would have solved the mystery in the field. The larger size of the disks seemed to rule out Trapeliopsis which is generally under 1.5 mm., but just in case I had a whole forest full of atypical specimens (not likely!), chemical testing was in order. Upon applying a drop of bleach to one disk, it turned distinctly red, as did the thallus when the bleach came into contact with it during a second test. Given that the specimen was taken from Doug fir and that it showed a C+ reaction in both the thallus and apothecia, I am confident in stating that the lichen in the photo is Ochrolechia oregonensis, Double-rim Saucer Lichen. Its close cousin O. laevigata (Smooth Saucer, featured previously in this blog) grows on deciduous trees as opposed to conifers.
365Caws is now in its 14th year of publication, and was originally intended to end after 365 days. It has sometimes been difficult for me to find new material, particularly during the winter months, but now as I enter my own twilight years, I cannot guarantee that I will be able to provide daily posts. It is my hope that along the way I may have inspired someone to a greater curiosity about the natural world. If so, I can rest, content in the knowledge that my work here has been done.
Friday, February 19, 2016
A Positive Reaction
My sample was collected from a Douglas fir (Pseudotsuga menziesii), the first clue as to its identity. However, I was not certain that I was observing a secondary interior exciple ring in the well-developed disks, a feature which would have solved the mystery in the field. The larger size of the disks seemed to rule out Trapeliopsis which is generally under 1.5 mm., but just in case I had a whole forest full of atypical specimens (not likely!), chemical testing was in order. Upon applying a drop of bleach to one disk, it turned distinctly red, as did the thallus when the bleach came into contact with it during a second test. Given that the specimen was taken from Doug fir and that it showed a C+ reaction in both the thallus and apothecia, I am confident in stating that the lichen in the photo is Ochrolechia oregonensis, Double-rim Saucer Lichen. Its close cousin O. laevigata (Smooth Saucer, featured previously in this blog) grows on deciduous trees as opposed to conifers.
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