Alectoria ochroleuca

[ralfwagner]

Hello,

Alectoria ochroleuca is a lichen that can be found in alpine heathlands on acid soil. This one is from Tyrol, Austria.

- Thallus, 8 - 12cm , erect or sprawling, modeerate branched, branches up to 2 mm diameter, yellowgreen to bright green. Apex often black. Elongated, bright pseudocyphellae, often black pycnidia at the apices. Chemistry: Medulla: CK + yellow (diffractic acid), cortex: KC+ yellow (usnic acid).



- Closeup thallus with longish pseudocyphellae. 25 pictures stacked with Zerene stacker.



- Closeup apex with black pycnidia. 30 pictures stacked with Zerene stacker.



- Cross section branch. In contrast to Usnea there is no (compact) central axis with Alectoria; staining with Lactophenol-Methylblue-Acidfuchsin.



- Cross section branch.

[BJ]

Ralf,


I particularly like the third photo as it has a good 3D feel, with the lichen standing out from the background.

In my ignorance i would have definitely called it an Usnea !

Is the lack of central tissue a clear discriminator between the two genera....and is it obvious in the field if you just cut through a branch ?

Thank you for posting again!

regards
Brian

[Mitch640]

Very nice images, even if I don't know exactly what they are.

[ralfwagner]

Hello,

the lack of a central tissue is the most obvious and clear discriminator between Alectoria and Usnea.

This an example for Usnea:


Usnea fulvoreagens, cross section branch, oblique ill.


Usnea fulvoreagens, cross section branch, phasecontrast


In the field this can be easily examinated with th aid of a magnifying glass (10x).

Thanks for your kind comments.

[Charles Krebs]

Ralf,

I find the last two images in your initial post not only informative but aesthetically quite pleasing!