ABSTRACT: This study examined the zonal distribution of myxomycetes in the Pacific Northwest, with special emphasis on the forests and woodlands of western Oregon. Our material included specimens of at least 77 species of myxomycetes, many of which occur mainly on wood or bark. Most specimens were obtained from moist chamber cultures. Elaeomyxa cerifera is reported as new for North America north of Mexico; this species, one species of Cribraria, and two species of Licea are described in detail. According to our data, species richness and productivity of myxomycetes are highest in the mixed forests and woodlands of inland valleys. Wet coniferous forests at both ends of an elevational gradient exhibit lower values of species richness and productivity. The main pattern observed is that of increasing myxomycete diversity with increasing heterogeneity in substrate types, especially in relation to increasing availability of angiosperm bark and wood among potential substrates for myxomycetes.

KEYWORDS: Myxomycota, vegetation zones, Elaeomyxa

NOMENCLATURAL NOVELTIES: None.