Umbilicaria polaris

Family / Families: Umbilicariaceae
Scientific Name(s): Umbilicaria polaris (Schol.) Zahlbr.
Location(s): Yakima Canyon, Washington, USA
Entry Author(s): Daniel Mosquin
Copyright Holder(s): wanderflechten@Flickr aka Richard Droker
Image Permissions: Please contact the copyright holder for permission to use.
Photographer(s) Appreciation: Thank you to Richard Droker aka wanderflechten@Flickr for sharing this photograph of Umbilicaria polaris. Your lichen photographs are always appreciated!
Tags: Lichen, Umbilicariaceae, USA, Washington

Umbilicaria polaris, or lesser salted rocktripe

For many years, North American lichenologists (mis)applied the name Umbilicaria krascheninnikovii to Umbilicaria polaris. This was only rectified in recent years in a 2011 paper by EA Davydov et al. in Herzogia 24:251–263: Contribution to the Study of Umbilicariaceae (Lichenized Ascomycota) in Russia. II. Kamchatka Peninsula, where the authors note that Umbilicaria krascheninnikovii is actually Umbilicaria polaris for North American records. The lichen from Washington state in today’s entry was originally submitted as Umbilicaria krascheninnikovii (hence some of the comments), but the name and entry have now been updated to reflect the misapplication of the name.

Interestingly, the two species are quite distinctive from one another, so it is not a case of mistaken identity through an identification process. Rather, the accumulated work in North America began with a wrongly-applied name; the error was compounded as references were built upon earlier texts and people used the name (albeit, incorrectly). Here are notes on the differences between the two species from the above paper:

Umbilicaria krascheninnikovii has a diminutive thallus (1–1,5cm in diameter), is coarsely pruinose with crystals located centrally near the umbo without a distinct reticulate pattern, and has sparse light brown to brown small (5,5–6,5 µm in diameter) thalloconidia on the lower surface. Umbilicaria polaris is medium-sized (2–3 cm in diameter) and has a well-developed prominent rough reticulate pattern that may be limited to the central part or cover the whole thallus; the lower surface lacks thalloconidia.

The reticulate, or net pattern, is aptly-illustrated in today’s photograph.

While Umbilicaria polaris is named after “north”, Umbilicaria krascheninnikovii was named in honour of the explorer and naturalist Stepan Krasheninnikov. Krasheninnikov started his exploration work of Siberia and Kamchatka at the age of 20, as one of the members of the eleven-year long Great Northern Expedition.

In addition to some variation of lesser salted rocktripe as a common name for both species (e.g., salty rocktripe), Umbilicaria krascheninnikovii is also known as Krasheninnikov’s navel lichen. As a group, Umbilicaria are known as the navel lichens–so that species wasn’t named after Krasheninnikov’s belly-button specifically, if that thought crossed your mind. Peruse through other images of Umbilicaria to reinforce the association, though.

As noted above, Umbilicaria polaris seems to be restricted to North America, while Umbilicaria krascheninnikovii is seemingly endemic to east Asia. Umbilicaria polaris is typically associated with siliceous rock substrates, though in this instance Richard found it on basalt. Basalt is considered to have a relatively low silicon dioxide content, at least in comparison with other igneous rock types.