A Review of the Anamorph GenusHelicomyces

Abstract

This paper reviews the taxonomic status of the anamorph genus Helicomyces. Updated descriptions and keys to the eleven accepted species are provided. Helicomyces louisianensis is described as a new species; H.fuscopes is regarded as a synonym of H. roseus Link. Twentythree excluded species are listed and their current taxonomic placement indicated. The genus Helicomyces was established in 1809 by Link, making it the oldest of all the genera of helicosporus Hyphomycetes. As pointed out by Linder (1929), Helicomyces became the historical meeting ground for all helicosporous species in which the conidia and conidiophores are hyaline. Linder (1929) redefined the genus, separating it from Helicosporium in a purely arbitrary manner on the basis ofthe presence of elongate and conspicuous conidiophores . in Helico? sporium. Helicoma was distinguished from Helicomyces on the basis of the nonhygroscopic, relatively thick-walled conidia found in Helicoma. Many of the species originally assigned to Helicomyces were reassigned by Linder to Helico? sporium or Helicoma. Linder's treatment has been accepted by most students of the group, making his monograph the appropriate departure point for a review. Linder recognized five species of Helicomyces: H. ambiguus, H. bellus, H. roseus, H. scandens, and H. tenuis. Moore (1955) included these five species plus H. colligatus Moore and H. fuscopes Linder in his key, which was essentially an expansion of Linder's treatment to include species described subsequent to the appearance of Linder's monograph. Four species have been described since Moore published his key, and additional distribution records for other species have accumulated. This paper reviews the current status ofthe genus Helicomyces in an effort to provide a basis for future re-assessment. In the course of this review, I have examined herbarium material kept at the Farlow Herbarium (FH), The New York Botanical Garden (NYBG), The National Fungus Collections (BPI), The Com? monwealth Mycological Institute (IMI), Iowa State University (ISC) and the Uni? versity of Rhode Island (KIRI). Much of the material in FH was studied and determined by Linder. In the course of this study, three collections assigned to H. roseus were encountered which appear to be incorrectly placed in that species. Two ofthe collections are in NYBG (Langlois No. 2188 and Rogerson, 1960, Baton Rouge, LA), and one is in FH (Neon No. 1995); all three specimens are from Louisiana. A new species is erected to accommodate these specimens. Pirozynski (1972) pointed out the close similarities between H. fuscopes and H. roseus, and suggested that the two species may be conspecific. Linder distin? guished the two species primarily on the basis ofthe dilute fuscous conidiophores in H. fuscopes and the hyaline conidiophores in H. roseus, a characteristic which is difficult to apply consistently. In my study, I have examined about forty spec? imens from many geographical sites, assigned to either H. roseus or H. fuscopes and find no consistent basis for separating the two species. Material assigned to H. roseus by Linder could be placed equally well in H. fuscopes. One can find