A New Taxonomy for the Cetraria ciliaris Group

Abstract

The Cetraria ciliaris group is composed of four species. Cetraria ciliaris Ach. produces olivetoric and physodic acids and occurs in eastern North America and Finland. Cetraria halei W. Culb. & C. Culb. sp. nov. is mor- phologically identical to C. ciliaris but produces alectoronic acid and, as an accessory substance, o-collatolic acid. It occurs in eastern North America and in the Old World from Finland through the Soviet Union to Japan. Although through much of their collective North American range C. ciliaris and C. halei are sympatric, C. ciliaris is more southern in its qualitative and quantitative dis- tribution and C. halei more northern. Certraria microphyllica W. Culb. & C. Culb. sp. nov., an endemic of Hokkaido, is the second known lichen to produce the rare substance microphyllic acid. Cetraria orbata (Nyl.) Fink produces protolichesterinic acid and has a disjunct range in eastern and western North America. All the species except C. orbata produce the cortex substance atranorin. The lichens collectively called Cetraria ciliaris are familiar to cryptogamic botanists in the northeastern United States. The plants are commonly seen on the trunks and branches of pines and other conifers from southeastern Canada to the Lake States and south throughout the Appalachian Mountains and associated foothills. The species group is also widely distributed in the Old World, occurring from Finland through the Soviet Union to Japan. In 1963 Hale published a study in which he showed that the American representa- tion of the C. ciliaris group consists of three chemically different types, which he interpreted as strains. Two of the three strains were very abundant in the Appa- lachian Mountains along the Virginia-West Virginia border and made up almost the entire representation of the C. ciliaris group there. In that region Hale carried out a gigantic field survey involving the analysis of 16,398 specimens of the C. ciliaris complex taken from randomly selected trees in 218 woodland stands. He demon- strated a surprisingly complex and highly patterned variation from stand to stand in the proportion of the C. ciliaris populations producing olivetoric acid as opposed to those producing alectoronic acid. From his results he concluded that there seems to be no microclimatic factor that can be correlated . . . with the general distribution (of the chemically different plants.) . . . The fact that within a group of adjacent woodlots the percentage of plants with each acid remains essentially constant regardless of exposure, height on trees, and nature of substratum, offers strong evidence that