Recognizing the Target Species

If a specimen matches the field characteristics for one of the target species, make a small collection for later confirmation. We suggest using the following characteristics for each species in the order listed to maximize efficiency. Also, see the photos.

Lecanora conizaeoides

Field characteristics:
Greenish gray crustose thallus
Greenish or greenish gray soredia usually across entire thallus
Pale brown apothecia with sorediate margin
Prefers exposed areas to deep shade

Look alikes:
Similar in appearance to green algae, but prefers exposed areas and is has a more patchy growth form than green algae. A number of other sterile crustose lichens are similar in color and form and must be separated with a P test (see below)

Further lab checks:
Thallus P+ red-orange

Physcia millegrana

Field characteristics:
Small white or light gray thallus, appressed
Appears somewhat broken-up, no long fine lobes.
NO cilia present (use hand lens!)
Granular soredia, NOT hooded (use hand lens!)

Look alikes:
Physconia spp. -- Pruinose and usually more brown in color.
Phaeophyscia spp. -- Usually darker gray, cortex K-
Physcia adscendens -- CILIA present, thallus not as apressed.
Physcia tenella -- CILIA present, soredia underneath lobe tips.
Physcia duplicorticata -- known only from the San Francisco Bay area (Weber & Thomson 1975). Very similar to P. millegrana. According to Weber & Thomson, P. duplicorticata is "a slightly coarser plant with thicker thallus" (see their paper for anatomical differences). "The marginal granules on the lobes have more the appearance of minute lobules than in P. millegrana in which they are more granular to isidioid-granular , and are coarser than in P. millegrana."

Further lab checks:
Cortex K+Y, lower surface pale

Phaeophyscia rubropulchra

Field characteristics:
Small light gray thallus
Medulla bright red-orange when exposed_expose medulla by scratching thallus with a fingernail or knife (use hand lens!)

Look alikes:
Phaeophyscia orbicularis -- Medulla not red-orange.

Further lab checks:
Cortex K-
See key in McCune & Geiser (1997)

Punctelia subrudecta

Field characteristics:
Lower surface light brown
Pseudocyphellae punctiform (appear as small spots or hollows) and do not appear as cracks

Look alikes:
Parmelia sulcata -- Lower surface black, pseudocyphellae appear as cracks.
Note: so far we have not attempted to separate this species from Punctelia perreticulata, a nearly identical variant separated only by conidial characters (Adler & Ahti 1996: Lichenologist 28:431-436.).

Further lab checks:
Medulla KC+R
See further information in McCune and Geiser (1997).