Parmelia sulymae

The thallus (the lichen body) is foliose, typically 5–8 cm across (occasionally to 12 cm), and attached flush to the substrate. Lobes are narrow, usually 1–2 mm wide (rarely to 3 mm), elongate and irregularly branched, and tend not to overlap. The upper surface is pale greenish‑grey to bluish‑grey, sometimes brownish at the tips, and may show fine white dots or lines called pseudocyphellae, which are tiny breaks in the skin that help with gas exchange and often form low net‑like ridges with age. Vegetative reproduction is by compact granules the authors call "sorsidia" (their term for tightly packed soredia). Soredia are small powdery packets of fungus and algae that flake off and start new lichens; in P. sulymae these are denser than usual and commonly start at the lobe edge before spreading over the surface along the pseudocyphellae. The lower surface is dark brown near the tips but otherwise black, smooth and shiny, with abundant rhizines (minute, hair‑like anchors) that often fork from their base; on this species they can reach about 1–1.5 mm long and extend right to the lobe tips. Sexual structures are uncommon: apothecia (disc‑like spore cups) are rare and abortive in the material examined, and pycnidia (asexual spore organs) were not seen. …

Parmelia sulymae is characteristic of mature, humid forests. It is most often found on the branches and upper trunks of conifers—especially fir (Abies), spruce (Picea), and hemlock (Tsuga)—and only rarely on deciduous trees such as balsam poplar (Populus balsamifera). Field notes emphasise cool forest microclimates with intermittent sunfleck. The species occasionally occurs on rock (saxicolous) in sheltered outcrops, where its appearance can be coarser. The known range is restricted to north‑western North America. Most records are from low to mid‑elevations in humid parts of intermontane British Columbia, Canada, with additional collections from adjacent Idaho, USA. A few coastal occurrences are documented, apparently confined to the middle and upper tree crown. Compared with P. hygrophila, a better‑known regional endemic, P. sulymae is described as more hygrophytic—more tied to persistently moist forest air.

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