Multivariate analysis of the Scutellinia umbrorum complex (Pezizales, Ascomycetes) from five ecotopes in the Netherlands

The multivariate structure of the Scutellinia umbrorum complex ( Pezizales, Ascomycetes), based on the morphometrical parameters of 81 specimens from five ecotopes in the Netherlands, was analysed. According to conventional expert estimation, five putative taxa resp. species were established: S. patagonica (Rehm) Gamundi, S. aff. subhirtella Svrček, S. umbrorum (Fr.) Lambotte, S. parvispora J. Moravec and S. subhirtella s. Kullman. These taxa form a taxonomic continuum hardly separable by traditional taxonomy. Five clusters obtained by UPGMA (with the generalized J-distance for mixed data as a measure of resemblance) are more distinct and in good accordance with ecological factors; some of them, however, are statistically not well separated. The revision of the clusters’ structure by k-means approach yields highly discontinuous clusters. The morphometric characters of specimens differ when going from open habitats to the forest. Differences are also revealed in phenology: the growing season starts in the forest later than in open habitats. The data are divided into two subsets according to spore ornamentation and spore width, the withingroup variation of either subset is caused mainly by the length of marginal hairs. On the basis of several statistical methods a supposition was introduced that the S. umbrorum complex probably consists of two polymorphic species, S. umbrorum (Fr.) Lambotte and S. subhirtella Svrček s.l., with the mean value of marginal hairs longer than 450 µm and shorter than 450 µm, respectively. The UPGMA clusters can be interpreted as ecodemes of respective species.