Distribution of Chemotypes of Rhizoplaca in North America

摘要: Considerable chemical variation was found in two of the six currently recognized species Rhizoplaca North America. In most widespread species, R. chrysoleuca, common chemotypes are largely sympatric; however, rare mainly restricted to Southwest, and only arefound Eastern andAppalachian regions. Chemical also within individual packets chrysoleuca. The melanophthalma almost completely were West. Despite sympatry, quantitative latitudinal differences proportional representation different lichen substances: usnic acid northward, psoromic, lecanoric, pseudoplacodiolic acids at low latitudes. A key American incorporating secondary chemistry is given. Variation secondary-product con- tent poorly known. three Eurasian ofRhizoplaca surveyed world-wide by Leuckert et al. (1976). present paper builds upon their foundation with a more intensive sample Rhi- zoplaca, including several endemic America (Weber 1979), an aim (1) describe distribution genus Rhizoplaca, (2) provide that incorpo- rates this understanding chemotypes.