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When: 2008-10-15

Collection location: Forest near Elgin St., Pembroke, Ontario, Canada [Click for map]

Who: Paul Derbyshire (Twizzler)

No specimen available

I’m not sure what caught my eye from a distance, but up close the large, bright yellow apothecia were gorgeous!

Edit, June 11 2009: swung by these to see how they were doing, and added a fresh closeup of the same group of apothecia featured in the thumbnail.


Proposed Names

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By: Paul Derbyshire (Twizzler)
2008-10-19 02:53:36 BST (+0100)

The first image on this observation is a cropped thumbnail based off the closest of the three actual photos taken. The second image is this closest photo, at full resolution and un-cropped. The third and fourth are photos that show how this lichen was distributed on a birch tree, and what it looks like from a typical walking-by-the-tree distance.

The more distant shots were handheld; the closeup was a tripod shot, set up straddling the branch below the cluster(!).

I see rhizines
By: Jason Hollinger (jason)
2008-10-18 21:18:03 BST (+0100)

Recently Xanthoria was split into two genera. Species without rhizines (or with stubby ones called “hapters”) remain in Xanthoria; ones with rhizines (more than half, I think) moved to Xanthomendoza. (Lindblom cites Arup and Grube 1999, and Sochting et al. 2002 for the studies proving they form separate lineages.)

In the fullsize copy of the “distant” photo (which ironically has much more detail than the “close-up”! :), you can clearly see loads of short rhizines, and in particular you can see them sprouting from under the margin of most of the apothecia. This places it firmly in the new genus, Xanthomendoza.

The salient features at this point are: mounded habit (as opposed to being a mostly-appressed rosette like Xanthoria parietina or X. elegans), and abundant apothecia (as opposed to breaking up into piles of granules like, say, Xanthomendoza fulva). The two species that match this are Xanthomendoza montana and X. hasseana. They are difficult to tell apart where their range overlaps, but fortunately in Ontario it can only be the latter (I think).

According to Lindblom in the treatment for Xanthomendoza in Lichen Flora of the Greater Sonoran Desert Region, Vol. II (where the two species overlap), X. hasseana has “slightly longer and narrower lobes that are usually lighter orange pigmented, smaller and more distinctly ellipsoid spores with a wider septum… the rhizines as well as cilia on the thalline margin of the apothecia are usually longer”. They don’t ever actually grow together, X. hasseana preferring lower, moister regions (coastal in Caifornia, for example, and across Canada), while X. montana prefers the arid interior (the Rockies and mountains of California).

See Brodo’s Lichens of North America or McCune’s

By: Paul Derbyshire (Twizzler)
2008-10-18 04:16:00 BST (+0100)

View the second photo at full resolution. That area is in there, at about 4x the detail.

nice thumbnail
By: Debbie Viess (amanitarita)
2008-10-18 03:40:44 BST (+0100)

sure would be sweet if we could enlarge it for detail.

I agree
By: Irene Andersson (irenea)
2008-10-17 21:07:44 BST (+0100)

If this is Xanthoria polycarpa, I can’t find any evidence that it has been renamed.

Naming oddities.
By: Paul Derbyshire (Twizzler)
2008-10-17 20:27:32 BST (+0100)

For some reason, the genus name Xanthoria appears to be deprecated, but no preferred synonym is listed. Four species are listed, of which two are deprecated, both in favor of Xanthomendoza.

Has the whole genus been renamed to Xanthomendoza, then? If not, then what?