from the November 16, 2014
Newsletter issued from Río Lagartos, on the north-central coast of Yucatán, MÉXICO
POWDERY TWIG LICHEN
Both mushrooms and lichens are uncommonly seen in the area around Río Lagartos. The largest lichen I've yet seen here, about the size of a turkey egg, is shown above. A close-up of the granular-textured, ribbonlike body with cuplike apothecia appears below:
This fruticose, or shrubby, lichen with its color, form and habitat reminded me of the Cartilage Lichen we saw back in Texas, which you can compare at http://www.backyardnature.net/n/x/ramalina.htm.
Cartilage Lichen is a member of the genus Ramalina, so I did a web search on Ramalina lichens found in the Yucatan and what turned up looked pretty much like what's in our picture. It was the Powdery Twig Lichen, RAMALINA POLLINARIA, one of a few species known to occur worldwide. It's described as having a very variable morphology, and it's true that many images of the species on the Internet look a bit different from ours, but some look practically identical. The species description at LichenPortal.Org says that usually it occurs on rock, but sometimes on twigs, like ours.
Our twig lichen was on a dead twig along a road through the savanna east of town, south of the mangroves.