XANTHOMENDOZA FALLAX, THE HOODED SUNBURST LICHEN
The following photograph was taken of lichens on the bark of a balsam poplar tree beside Erskine Lake in south-central Alberta on March 27, 2013. The yellow one is the lichen Xanthomendoza fallax. This lichen is very common in on the bark of poplar trees in southern Alberta. The color ranges from orange to yellow, however, it can be yellowish green when wet.
Lichens are unique in the Plant Kingdom as each “species” is made up of a union of algal cells and fungal hyphae that are so symbiotically in union that the alga contributes food through photosynthesis and the fungal hyphae provide the substrate that holds the algal cells in place.
Lichens receive moisture through rain and dew and nutrients from dust that settles out on them.
Lichens can be crustose as in this case, when closely attached to the substrate, foliose when broad and loosely attached, or fruticose, when branched and attached at one basal point.
The taxonomy of lichens has been undergoing change as studies in chemistry and DNA have been revealing new information about relationships. Along with this, the genus name of this lichen has been changed from Xanthoria to Xanthomendoza.
Many additional lichen species occur on tree bark. The grey ones in the photograph are an example.
The very best source of information on this and other North American lichens is Irwin Brodo, Sylvia Duran Sharnoff and Stephen Sharnoff’s 2001 book “Lichens of North America”.
See http://www.sharnoffphotos.com/lichensH/xanthomendoza_fallax.html, for additional images.
When going on your next winter hike, take a close look at the bark of poplar trees. You may be surprised at all the life that is there.