MOLECULAR SYSTEMATICS OF UNITUNICATE PERITHECIAL ASCOMYCETES - THE CLAVICIPITALES-HYPOCREALES CONNECTION

Cladistic analysis of partial sequences (840 nucleotide positions) from the nuclear encoded small subunit ribosomal DNA was performed to infer the higher taxonomic placement of the Clavicipitales within unitunicate perithecial ascomycetes. Two major classifications exist concerning the placement of this order of ascomycetes; one places it as a sister group to the Hypocreales and the other, as a member of or a near relative to the Xylariales. A strict consensus of 10 equally most parsimonious trees was in agreement with the placement of the Clavicipitales as a monophyletic sister group to the Hypocreales; relationships within the Clavicipitales were not fully resolved in the strict consensus. The taxa sampled from the Hypocreales comprised a paraphyletic lineage in the strict consensus. Characters derived from anamorphs, stromata, centrum anatomy and nutritional modes were reviewed with respect to their level of congruence with the results inferred from the molecular data.