Observation 96408: Dirina massiliensis Durieu & Mont.
When: 2012-06-02
Collection location: Peniche, Portugal [Click for map]
Who: zaca
No herbarium specimen

Notes: Growing on the man made wall that surronds the terrestrial part of the city for centuries.
This was a nice surprise. I take a bit of time to understand to which genera these specimens belong. Without microscopy after trying some keys I get confused. After microscopy, using other key with micro details, I came to the genus Lecania for the first time. Then I saw the spores of some species and I get convinced: the genus was found. But, the species seems to be a lot more difficult.
Some features of these specimens:
- Thallus whitish to light gray with 3-4 cm across; areolate with flat and angular areolas;
- Apothecia sessile with a thick rim, some developing in clusters; discs brown almost all covered with a dense pruina concolor with thallus;
- Brown epihymenium; hialine hymenium; dark brown hypothecium;
- Paraphyes hialine and very narrow;
- Asci clavate of Bacidia-type, 8-spored;
- Spores hialine, mostly 3-septate and encurved, with the following average dimensions: Me = 24 × 3.5 µm.

From the descriptions availabe in CNALH for the species in this genus, the only one I found with some similar features was L. coeruleorubella, which in general presents a more colorful thallus.

Proposed Names

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Used references: CNALH.
Based on microscopic features
Based on chemical features
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Add Comment
No problem
By: Jason Hollinger (jason)
2012-06-08 02:09:51 CEST (+0200)

My only concern is that Dirina massiliensis (all of the Dirina in the Sonoran Flora actually) is supposed to have lecanoric acid, which is C+ strong red. Maybe the concentration was just really low in your specimen. Or can your C reagent have gone weak? It can out-gas quickly depending on how often you open or shake the bottle (e.g. while carrying it in the field).

…Just checked, none of the species of Lecania in the Sonoran Flora have C or KC reactions. Adds more weight to your faint C/KC+ pinkish thing.

If the alga is Trentepohlia …
By: zaca
2012-06-08 00:39:38 CEST (+0200)

certainly Dirina massiliensi is the best choice.
Thanks, Jason, for the help.

Yes, that could be
By: Jason Hollinger (jason)
2012-06-08 00:03:05 CEST (+0200)

Trebouxia shouldn’t be so yellow/brownish.

This has a fair comparison of the two:


Here’s another okay shot:


Neither really shows the clear golden oil drops that I’ve seen from time to time. But it certainly shows how similar the two can be!

I uploaded a set …
By: zaca
2012-06-07 23:52:07 CEST (+0200)

with the possible photos showing the photobiont. According to your explanation, it must be Trentepohlia, but …
By the way, for further reference, can you indicate me a photo of an apothecial section from which one could infer that the photobiont is Trentepohlia?

Distinguishing Trebouxia and Trentepohlia is harder than it should be
By: Jason Hollinger (jason)
2012-06-07 20:32:26 CEST (+0200)

I guess once you get get at it, it’s obvious, but…

Both can be globose. If you see filaments, then absolutely, no question it is Trentepohlia. If globose, look for golden oil drops (Trentepohlia). I have been incapable of getting a good photo of this. It is important that you check in water, not KOH or stained with anything. Fortunately, structure is unimportant, so you can squash the heck out of it, and you can just mount scrapings instead of trying to make the perfect apothecial section. (The latter is always better anyway, though, as it gives you everything you need in one go. Definitely worth practicing making good sections!)

Very good keys you have, Jason.
By: zaca
2012-06-07 20:10:47 CEST (+0200)

I saw Dirina massiliensi form sorediata in lastdragon and looks very different, due to soredia and lack of apothecia. But then I saw in EOL the form massiliensis, curiously the photos are from a portuguese photographer, and indeed is very similar to mine, though the thallus is darker and apothecia are less pruinose. In bgbm the photo for D. massiliensis f. massiliensis seems to be a perfect match. Another photo very similar can be seen in British lichens where the two form stand side by side.
On the other hand, I was looking again to the photos from microscopy and I not not able to see any algal cell, not even in the apothecial sections where usually is visible, depending on the photobiont. As far as I remember, if the photobiont is Trebouxia I must see some green globose cells, whereas if it is Trentpohlia some filaments should appear, though these must be more difficult to see with my equipment because could be scrambled with paraphyses and other structures.

British Flora is no help
By: Jason Hollinger (jason)
2012-06-07 03:19:48 CEST (+0200)

I get either Dirina massiliensis (C+red and spores 4-6µm wide, but otherwise extremely similar to what you have), or Lecania suavis or L. nylanderiana but both of those have dark to black margins(!)

Be sure to check both chlorococcoid (e.g. Trebouxia) and Trentepohlia genera for these crusts. I’ve made some real big mistakes by just assuming the algae was Trebouxia. (Dirina has Trentepohlia, Lecania has Trebouxia.) This usually splits out at the very top of any key to crustose genera, so it’s easy to miss if you jump straight to crusts with hyaline septate spores.

Created: 2012-06-05 20:02:16 CEST (+0200)
Last modified: 2012-06-08 20:20:51 CEST (+0200)
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