The Hypogymnia Species of North America

Interactive Key

Select characteristics
 Click on characteristic name for help
Regional Abundance
Substrate Bark or Wood Rock or Ground
Vegetative Structures
Habit Appressed Yes No
Habit Pendulous Yes No
Habit Erect to Suberect Yes No
Size cm
Upper Color- White to Greenish Gray Yes No
Upper Surface Brown when Solarized Yes No (black,gray,unknown)
Dark Mottles Yes No
Black Border Yes No
Lobes Separated Yes No (contiguous)
Lobe Outline Pinched and Swollen Even or Elongate
Upper Surface Texture Rugose Smooth to weakly rugose
Branching Isotomic dichotomous Variable,irregular or pinnate
Budding Yes No
Lobe Width mm
Lobe Tips, Axils, and/or Lower Surface Perforated Yes No (entire)
Cavernulae Present Absent
Thallus Texture Papery Cartilaginous
Medulla Hollow Solid
   Ceiling Color Dark White
   Floor Color Dark White
Reproductive Structures
Soredia Yes No
   Soredia Texture Powdery Granular
   Soredia Terminal or Laminal Terminal Laminal
   Soredia Shape Lip-Shaped Yes No
   Schizidia Yes No
   Isidia Yes No
Lobules Yes No
Apothecia Yes No
   Spore Length µm
   Spore Width µm
Pycnidia Yes No
Hypothecium POL+ Not
Medulla P Test P+ or Orange P- or pale Y
Medulla K Test K+ or RedBrown K- or weak brown
Medulla KC Test KC+ or Orange KC-
Physodic acid by TLC Present Absent
3-hydroxyphysodic acid by TLC Present Absent
2'-O-methylphysodic acid by TLC Present Absent
Physodalic acid by TLC Present Absent
Hypoprotocetraric acid by TLC Present Absent
Diffractaic acid by TLC Present Absent

Tips for using this key:

  • Please read Characteristics page if you are not familiar with lichens or Hypogymnia.
  • Select a couple characteristics and click the 'Search' button.
    • Interpreting results:
    • Greenness indicates match to likely species. Purpleness indicates mismatch to likely species.
    • Species values for quantitative characteristics are shown as Mean (± Standard Deviation)
    • Species values for boolean characteristics are shown as 'Value (Probability)'. Ex: 'Yes (0.9)' indicates among individuals of this species, 90% will have this particular characteristic.
    • Score : Relative probability among 31 North American species
    • Fit : How well do the selected characteristics match. Red indicates bad fit.
  • If a species has a relatively high Score (from 0 to 100) compared to other species and good Fit (above 50%), click on the name to look at the species page.
  • If several species have scores within 4x, try selecting more characteristics, with particular focus on those marked with orange stars (*), which indicate most discerning characteristics among the most likely species.
  • If the most likely species all have bad fit scores, check your selections carefully.