Identification: Common lichen or fungus, but what is it?

I have seen these in the Northeast USA for years, but I don't know what they are. They're about 1/8 inch high and I photographed them today growing on an old wooden shingle roof.

 

A lichen of the genus Cladonia, of which there are 128 North American species.

 

Definitely a lichen; probably a Cladonia species.

 

I would guess Cladonia coccifera from where it was growing

 

I have a question. First I would definitely call it a Cladonia lichen and a even mention a soldier. What I do not understand is why it would be C. coccifera which I believe is a rare arctic-alpine lichen (according to Brodo et al.) and I would think not to be found in Pennsylvania. I would think it could be a plain old British Soldier (other than the grey stems).

 

I am almost totally ignorant about lichens, but a quick search on the web shows that Cladonia coccifera seems to be everywhere from Svalbard to Antartica, including Pennsylvania.

 

I have checked Ovstedal and Lewis Smith's Lichens of Antarctica and South Georgia and cannot find this species and rechecked Lichens of North America where coccifera is described as a rare arctic-alpine lichen. I would still have to say it is not coccifera, but I cannot do much more than suggest Cladonia.