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

Cladistic analysis of partial sequences (840 nucleotide positions) fro m the nuclear encoded small subunit ribosomal DNA was performed to inf er the higher taxonomic placement of the Clavicipitales within unituni cate perithecial ascomycetes. Two major classifications exist concerni ng the placement of this order of ascomycetes; one places it as a sist er group to the Hypocreales and the other, as a member of or a near re lative to the Xylariales. A strict consensus of 10 equally most parsim onious trees was in agreement with the placement of the Clavicipitales as a monophyletic sister group to the Hypocreales; relationships with in the Clavicipitales were not fully resolved in the strict consensus. The taxa sampled from the Hypocreales comprised a paraphyletic lineag e 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.