Sparassis (Basidiomycota): Transatlantic disjunction and paraphyly
R. PETERSEN (1), K. W. Hughes (1). (1) University of Tennessee, Knoxville, TN, U.S.A.
<i>Sparassis</i> can be conveniently divided into two complexes: the <i>S. crispa</i> complex, in which the ultimate branches of basidiomata are curled or crisped. Included species are <i>S. crispa</i> (typus generis), <i>S. radicata</i>, <i>S. latifolia</i> and a few others. The second complex, in which the branches are erect, stiff, blade-like and without curled or crisped margins, includes <i>S. spathulata</i>, <i>S. brevipes</i>, <i>S. laminosa</i> and some other names. Phylogenies based on ITS and LSU sequences show that the <i>Sparassis crispa</i> complex comprises several monophyletic clades, in some cases corresponding to named taxa (i.e. European <i>S. crispa</i>, American <i>S. radicata</i>), but in others lacking names (i.e. eastern North American <i>S. “crispa”</i>, southwestern American <i>S. “radicata”</i>). Morphological examination of numerous collections also distinguished subtle differences correlated with geographic distribution. Extensive sexual compatibility experiments indicate that monokaryon, haploid isolates of collections from North America and Europe are sexually intercompatible. Inherent in the study, three “species concepts” were tested, with the “biological species concept,” based on sexual compatibility, being the least restrictive.
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