Collection location: Parque de Monsanto, Lisboa, Portugal [Click for map]
The second photo is an enlargement of part of the first photo and serves to illustrate the axils open, which is a feature of this specimen. In the given reference I found three species with this feature:
- C. arbuscula (1);
- C. portentosa (2);
- C. crispata (3).
I proposed the third species for classification, since the first two have primary squamules absent.
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Thanks, Jason, for the information.
I was mixing up my techniques. This is from a draft manuscript for a lichen flora for British Columbia by Trevor Goward:
“Hutten technique: In a white ceramic spot plate (or on a microscope slide over white paper), submerge a small stem tip in a small drop of K. Leave to soak a moment, then add a tiny drop of C to the fragment, preferably using a pair of forceps. The sudden appearance of a golden yellow halo around the lichen confirms the presence of usnic acid. Should the K turn yellow before the C is added, proceed no further: your specimen, if it is a Cladonia, contains atranorin, and so won’t contain usnic acid.”
The “acetone extract method” is useful for the dark hair lichens such as Bryoria: (ibid)
1. Remove a small cluster of branches, taking care to include some branch tips.
2. Place these on a glass slide over a sheet of paper or other white background. (Better yet is to use a white porcelain spot plate).
3. Using a dedicated eye dropper, add just enough acetone to immerse the lichen (Acetone is available from hardware stores as resin thinner).
4. Allow the acetone to evaporate.
5. Carefully brush away the lichen fragments, leaving only the residue.
6. Apply a few drops of K (for example with a sewing needle), and record any colour changes (yellow, orange, or red).
7. After about two minutes, apply a drop of C to another part of the residue, allowing the C to partly overlap with the K.
8. Again record any colour changes, both for the C alone and where the K and C overlap.
9. Send a card of thanks to Bruce McCune and Roger Rosentreter, who came up with the technique.
“One variation of the spot test works well with slender, darkly pigmented lichens such as Bryoria. Squares of filter paper (or white paper towel or even white bond paper) about 1cm^2^ are placed on a microscope slide, which, for safety’s sake, is itself placed on a glass plate or disposable cardboard. Four or five filaments of the Bryoria are placed on the paper square and are then flooded with one or two drops of reagent… — enough reagent to leave the entire square wet. The reactive lichen substances will then dissolve in the reagent and flow out onto the paper from the cortex and exposed medulla (e.g., where the filaments are broken), and the color changes will be easily seen as the paper begins to dry.”
Brodo also describes a variant of the acetone technique: (he calls for a white porcelain plate with a depression instead of a glass slide over white paper)
[after acetone evaproates] “…allow a drop of K to run down one side of the depression to view the K color reaction on the residue, and do the same with C on the other side of the depression. The KC reaction will be observed where the two drops meet at the bottom of the depression.”
Lots of good ideas…
I interpreted incorrectly the ends of broken branches and you found the correct ones.
How is this Hutten technique performed? You cut a bit of the lichen and join a drop of acetone in a slide and let it evaporate?
The things you have circled are just the jagged ends of broken branches. Here’s another close-up of your photo with two axils circled (bottom one open, top one closed).
I find that the KC+ reaction from usnic acid in Cladonia is remarkably hard to diagnose correctly. I have recently discovered that my UV LED penlight does a much better job. (Although I find no record in literature of the bright UV+ yellow reaction I see.) Other techniques that might be more reliable involved using blotter paper to draw out the reaction into the paper so that it’s not obscured by the wet algae. The Hutten technique uses acetone to extract the lichen substances onto a glass slide. Once the acetone has evaporated, you can do spot tests directly on the slide (with white paper backing to allow you to see the color).
Created: 2010-07-24 14:12:29 PDT (-0700)
Last modified: 2010-08-14 11:38:51 PDT (-0700)
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