Pendent Usnea species were collected in western Oregon and examined.
Character states, such as cortex-medulla-axis ratio; fibril length; papilla diameter;
branching patterns; and presence or absence of fibrils, papillae, soredia, isidia; plus
chemistry, were recorded and analyzed by inspection for differences. Historical
names were researched in the literature. A comparison was made between species
concepts used in these accounts, with many conflicting concepts encountered.
Selected morphological characters were examined by scanning electron microscope,
or dissecting microscope, described, and illustrated. The characters reviewed
included articulate fissures; isidia and soredia; cortex-medulla-axis ratio; papillae; and
foveate pits. Species determinations were made for field collections. Names were
found for all specimens inspected without introducing new names at this time. Eight
pendent species were found in western Oregon; they are Usnea cavernosa, Usnea
ceratina, Usnea fillpendula, Usnea hesperina subsp. liturata, Usnea inflata, Usnea
leucosticta, Usnea longissima, and Usnea merrillii. A practical key to taxa with
descriptions is provided and geographic distributions are recorded in tables and maps
