Phylogenetic studies within the Pezizales. I. 18S rRNA sequence data and classification

The order Pezizales has been divided into two suborders. One suborder, the Sarcoscyphineae, was originally described to include members whose asci wer e characterized by an unusual apical structure, the suboperculum. Disagreem ents as to how this structure should be defined, and indeed, whether or not it exists at all, have rendered the status of the suborder controversial. The two families within this suborder are the Sarcoscyphaceae and the Sarco somataceae. Recent ultrastructural work demonstrates that there is an apica l thickening which is restricted to the Sarcoscyphaceae. In order to test t he monophyly of the suborders of the Pezizales and examine the relationship s within the Sarcoscyphineae, phylogenetic analyses were carried out using DNA sequence data from the 18S rRNA gene. The strict consensus tree based u pon these data shows both the Sarcoscyphineae and the Pezizineae as paraphy letic. These data suggest that the subordinal taxa currently recognized wit hin the Pezizales should be abandoned and the taxonomy revised to reflect p hylogenetic relationships. Strongly supported clades (i.e., greater than 95 % bootstrap value, 1500 replicates) include: the Pezizaceae, the Morchellac eae, the Sarcoscyphaceae, the Helvellaceae, and a clade that includes the S arcosomataceae (which is paraphyletic), and the Otidiaceae (represented onl y by 2 taxa). The genus Pindara, formerly placed in the Sarcoscyphaceae, is nested within the Helvellaceae, and Wynnea, assigned to the Sarcosomatacea e by some authors, is positioned in the Sarcoscyphaceae.