Observation 211966: Parmelia sulcata Taylor

When: 2015-07-30

Collection location: Rapid City, South Dakota, USA [Click for map]

43.9919° -103.3197° 1219m

Who: J-Dar

No specimen available

Occasional on Ponderosa Pine (Pinus ponderosa) in coniferous forest habitat.

Thallus blue-grey with white lines where the cortex breaks and soredia form. K+Y. Underside black to brown on lobe tips, rhizines abundant, black, stout, simple to forked at lobe tips, densely squarrose toward center. Medulla white, C-, K+R (burnt orange), KC+R (true red).

Proposed Names

77% (2)
Eye3 Eyes3
Used references: Wetmore 2005 (Revised): Keys to the Lichens of Minnesota
-28% (1)
Recognized by sight: Rhizines essentially simple, with few forked ones. No squarrose rhizines.

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Rhizines squarrose in center of thallus
By: J-Dar
2015-12-06 08:18:22 PST (-0800)

Those near lobe tips are simple to sometimes forked, but they are densely squarrose in the center of the thallus.

By: J-Dar
2015-08-10 09:54:29 PDT (-0700)

I’ll take another look at the specimen this week, and see if I can get some microscope photos of the rhizines, and I’ll update this observation. I have some collections to send to Esslinger, maybe he’ll take a look at this one for me too.

No, I can’t offer any better suggestions
By: Jason Hollinger (jason)
2015-08-10 08:17:20 PDT (-0700)

The Black Hills are most similar to the east slope of the Colorado Rockies, but there are no treatments for that region, either. Wetmore’s checklist is a fine example of thorough and insightful work, but alas, badly out-dated.

I’m not sure anyone really knows the full range of Parmelia barrenoae yet. But there are definitely specimens of P. sulcata with extremely sparsely branched rhizines. Personally, I refuse to put a confident name on a specimen until I see a branch of some sort: forked = barrenoae, squarrose = sulcata. There seems to be a good gestalt, but I don’t want to “jump the gun”! But this difference between squarrose and forked rhizines is a fundamental and reliable character for the genus as a whole, a really nice either-or character. So I’m sticking to it for now.

I was using Lichens of MN keys (Wetmore 2005)
By: J-Dar
2015-08-10 08:08:16 PDT (-0700)

and P. barrenoae isn’t in there. I struggled with this specimen because I could hardly call the rhizines squarrose, although some were slightly branched, thus my description “sometimes slightly squarrose or branched”. Can you suggest a better key for Black Hills lichens? I didn’t see much online other than Wetmore’s 1965 dissertation Lichens of the Black Hills, and P. barrenoae apparently was described in 2005 in The Lichenologist, so no help there either.

Only thing to watch out for is P. barrenoae
By: Jason Hollinger (jason)
2015-08-08 09:12:07 PDT (-0700)

Very similar to P. sulcata but the rhizines are all unbranched or occasionally forked, instead of squarrose with a bunch of minute perpendicular side-branches. (The soralia also tend to be more eroded, and the lobes therefore more bent back and loose from the substrate.) It’s very hard to diagnose confidently from photos.

Created: 2015-08-04 20:25:04 PDT (-0700)
Last modified: 2015-12-06 08:16:39 PST (-0800)
Viewed: 61 times, last viewed: 2017-08-18 12:58:32 PDT (-0700)
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