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I have tried all books and internet resources I know of, but I still have no idea what this might be — a lichen or something else.

At first glimpse, I thought it was something man-made and unnatural, but then I looked closer and saw how it appears to be attached and growing. It grows on exposed rocks well above the high tide. The photo is taken in late March, on northern Vancouver Island. It's loosely attached to the rock.

It was somewhat abundant around the general area (within of a few km), but I haven't seen it elsewhere - although I'm not from BC so there might be a lot of this around.

Orange Lichen The water droplet in the lower right corner give a rough sense of scale.

Edit: Adding another photo in which I just noticed a streak of white, which I included in original resolution. enter image description here

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    $\begingroup$ Possibly small (young) specimens of Usnea rubicunda $\endgroup$
    – RHA
    Apr 26, 2017 at 19:30
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    $\begingroup$ The growth pattern doesn't appear to match any photos or description of U. rubicunda I've seen, but it's not like I've got a better suggestion. Added a 100xp bounty to whoever gives a plausible answer. Maybe it's not even a lichen (But what else?). I regret not having taken a sample of it home, thought it'd be easy to identify given the color... $\endgroup$
    – Zewz
    May 1, 2017 at 21:17

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I want to propose you expand your search to a broader taxonomic scope. Specifically, I think you might be looking at a species of "red" green algae (family: Trentepohliaceae).

  • From Nelson et al. (2011):

    All Trentepohliaceae have filamentous growth forms and often contain large amounts of carotenoid pigments (ß-carotene and hematochrome), causing the algae to appear yellow orange in color (Thompson and Wujek 1997, Lo´pez-Bautista et al. 2002).

    • The Trentepohliaceae contains five genera: (Trentepohlia, Printzina, Phycopeltis, Cephaleuros and Stomatochroon) and 70+ species worldwide.

For example, the following algae (picture from England) looks fairly similar to your specimen:

Trentepohlia aurea

Trentepohlia aurea

Source: David Fenwick

If your specimen is a species in this family of algae, it is most likely in the Trentepohlia genus (or possibly Printzina genus).

Trentepohlia is a genus of filamentous chlorophyte green algae in the family Trentepohliaceae.

  • Typically orange or yellow in color.
  • Live on tree trunks and wet rocks or symbiotically in lichens.

Here's a picture of a free-living Trentepohlia species from coastal Oregon, USA:

Trentepohlia spp. on Cape Sebastian trail

Source: Richard C. Hoyer (2015)

  • The source notes that the specimen was simply ID'd as "Trentepohlia sp." by Tim Rodenkirk (Botanist with the Coos Bay BLM in North Bend, Oregon).
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    $\begingroup$ That seems like the right genus and I lift my hat in honor to you. Thank you for an excellent answer! I did doubt that it was a lichen, but I just couldn't think of what else it might have been as I was unaware of terrestrial algae with such a growth. $\endgroup$
    – Zewz
    May 2, 2017 at 22:44
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    $\begingroup$ Excellent find! I am surprised to see filamentous algae growing in such a dry habitat. Usually they grow under water or in very wet conditions. $\endgroup$
    – RHA
    May 4, 2017 at 8:33

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