Plants of the Gila Wilderness

Pseudevernia intensa is one of the easiest lichens in the forest to identify. It is a strongly branched grayish-white lichen with brown apothecia frequently present. The undersurface is gray. Dark spots (pycnidia) are easily seen with magnification on the upper surface especially along the margins. There are 8 elliptic single celled spores per ascus. The cortex is pale yellow in KOH, and the medulla is red in sodium hypochlorite. The photobiont appears to be Trebouxia. P. intensa is found on tree branches at upper elevation.
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Pseudevernia intensa, photo Russ Kleinman, Mogollon Mtns., Bursum Road, May 18, 2010

Pseudevernia intensa, growth habit, photo Russ Kleinman & Karen Blisard, Pinos Altos Range, McMillan Campground, June 19, 2018

Pseudevernia intensa, closeup of apothecia, photo Russ Kleinman & Karen Blisard, Pinos Altos Range, McMillan Campground, June 19, 2018

Pseudevernia intensa, undersurface, photo Russ Kleinman & Karen Blisard, Pinos Altos Range, McMillan Campground, June 19, 2018

Pseudevernia intensa, pycnidia, photo Russ Kleinman & Karen Blisard, Pinos Altos Range, McMillan Campground, June 19, 2018

Pseudevernia intensa, photomicrograph of cross section of apothecium, photo Russ Kleinman & Karen Blisard, Pinos Altos Range, McMillan Campground, June 19, 2018

Pseudevernia intensa, photomicrograph of cross section of apothecium with ascus in the center with 8 elliptic colorless spores, photo Russ Kleinman & Karen Blisard, Pinos Altos Range, McMillan Campground, June 19, 2018

Pseudevernia intensa, photomicrograph of cross section of apothecium in sodium hypochlorite with medulla turning red, photo Russ Kleinman & Karen Blisard, Pinos Altos Range, McMillan Campground, June 19, 2018