Vermilacinia polymorpha is a fruticose lichen infrequently found on Santa Catalina Island in the Channel Islands of California and along the mainland coast in Ventura and Orange counties.

It has also been indicated to occur south into northwestern Baja California without reference to specimens to support its range extension,[1] and shown to occur on the Vizcaíno Peninsula in central Baja California on a distribution map in a lichen flora, without reference to specimen data;[2] however, specimen data from other sources indicate it does occur as far south as Punta Santa Rosalillita on the main peninsula of Baja California,[3] and also reported from Guadalupe Island.

[4] Vermilacinia polymorpha may be recognized by a thallus divided into partly strap-like branches with irregularly widened parts, somewhat spoon-shaped, as shown in a “representative specimen” in the original publication by Peter Bowler and coauthors[1] reportedly collected by Richard E. Riefner Jr. (87-61a, IRVC)[5] from Aliso Canyon in Orange County, California.

The authors had noted that the species “most closely resembles a deformed N. robusta which has smaller spores of 10–12 μm, inflated, rounded branches, and larger urn-shaped apothecia.” Richard Spjut, in his revision of Niebla and Vermilacinia,[6] indicated that V. polymorpha is distinguished by the “oblong branches (less than 10 times longer than wide)”; he commented that some forms were difficult to distinguish from Vermilacinia robusta, while he was only able to briefly glance at the type while visiting Arizona State University in April 1996,[6] and that it is also distinguished by its smaller thallus with irregularly widened branches, compared to Vermilacinia paleoderma.

It differs in having irregularly widened branch parts near thallus base and narrower tubular segments above.