Pyxine subcinerea – The Lichen that Celebrates Halloween

This light gray foliose lichen is distinctive enough to field-recognize, at least to genus, with its linear pruinose-tipped lobes, but being small, is easy to miss—in the daytime at least.

But at night, with the aid of a UV flashlight, the so-called “jack-o-lantern lichen,” Pyxine subcinerea, stands out vividly as it fluoresces a brilliant golden yellow.

Ray Showman and Don Flenniken, in their landmark The Macrolichens of Ohio, published in 2004 by the Ohio Biological Survey, describe the ecology of this species as “Widespread in the southeastern US; common in southern Ohio, uncommon farther north, usually on bark, rarely on rock.” Their accompanying range map corroborates this, with circles (1945-1965) or squares (1965-2002) for nearly all the counties in the lower one-third of the state, but only three in the northern two-thirds. However, post-2002 records, gleaned from the Consortium of Lichen Herbaria (https//www.lichenportal.org) shows new records from the following 12 counties, here listed in order of increasing latitude, i.e., from south to north: Fayette, Montgomery, Franklin, Miami, Summit, Huron, Portage, Trumbull, Sandusky, Geauga, Ashtabula, and Lake. This seems to be a striking and sudden northward range expansion, perhaps, given its southern affinity, aided by a warming climate.

Personal anecdotal observations suggest that this lichen is noteworthy not only for the geographic breadth of its occurrence, but for its abundance as well. On the Columbus city street where the photo above was taken, there are 118 mature (>6 in. diameter) trees in the “devil strip” area between the street and the sidewalk. During a few early November nights this year I inspected them all with a UV flashlight and found Pyxine subcinerea growing on 70 of them (equivalent to 59.3%). The extent of colonization per tree was quite variable, ranging from just one or a few specimens <1 cm. wide, to instances where a dozen or more yellow patches, some several cm. across, could be seen.

One wonders whether this recorded range expansion and abundance is indeed a new phenomenon or just an increase in apparency brought on by the sudden availability and widespread use of UV flashlights. Readers, especially those in northern Ohio counties, are encouraged to acquire one of these gadgets and canvass their neighborhoods. It would be good to know if this lovely little showoff lichen is as abundant elsewhere as it is on my street.

-Bob Klips