When: 2010-10-26

Collection location: Philip Lake, Wells Gray region, British Columbia, Canada [Click for map]

Who: Jason Hollinger (jason)

No specimen available

growing on wet mossy boulder beside trail on mesic slope near ESSF

These photos were taken of the population at the type locality. (It’s only known from four or five locations worldwide, all in BC, Yukon and Alberta.)

It is useful to compare them to the other two sorediate Peltigera, P. extenuata and P. didactyla:

didactyla: disturbed soil banks
extenuata: sheltered mossy banks and rocks
castanea: open mossy rocks

didactyla: thallus simple, even cup-like raised margins, scattered
extenuata: thallus multi-lobed, wavy margins esp. in age, sprawling and overlapping
castanea: thallus multi-lobed, somewhat intermediate?, overlapping

didactyla: rhizines thin and pointed, bare near margin
extenuata: rhizines brush-like, forming projecting dense woolly mats right to the edge
castanea: rhizines brush-like but not densely matted, bare near margin

didactyla: nearly always becomes fertile in age
extenuata: very rarely fertile (I’ve never seen it)
castanea: not known to be fertile

didactyla: hairless or becoming tomentose near apothecia in age
extenuata: generally tomentose all over (not apparent when young and wet)
castanea: becoming densely tomentose mostly near the margins

The color also differs, but this is a hard character since it is so variable within each depending on age and moisture content. As the name would imply, castanea is browner. Also castanea turns dark underneath toward the center, while extenuata stays white to pale brownish even in old specimens.


compare the rhizines of this to those of Peltigera extenuata
This is the type locality.
Notice the brownish color, especially toward the older parts of the thallus at the top of the image.
Notice that the tomentum is primarly toward the margins.
Notice the well-developed veins which darken toward the center.

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