THE PERFECT STAGE OF FLAGELLOSPORA PENICILLIOIDES

Abstract

THE FUNGI IMPERFECTI are commonly reported components of the fresh-water floras of North Africa, Europe and North America. Many of these fungi, particularly representatives of the form family Moniliaceae, grow and sporulate while completely submerged; other representatives grow submerged but produce conidiophores that extend to the surface of the water before conidia are produced. On agar culture a small number of the species that produce conidia entirely beneath the surface of the water will sporulate aerially. Although an extensive literature concerning the distribution, taxonomy, culture and nutrition of these interesting fungi is accumulating (Ingold, 1942; Van Beverwijk, 1953; Ranzoni, 1951, 1953; Waid, 1954), no description of a sexual stage for any aquatic hyphomycete has been published. Acting upon the assumption that these organisms are heterothallic, the writer carried out a number of mating experiments in the attempt to induce a perfect stage (Ranzoni, 1953). Different strains of Anguillospora longissima (Sacc. & Syd.) Ingold, Tetracladium gracile Ingold, Clavariopsis aquatica De Wild. and Lemonniera cornuta Ranzoni were mated without success. In the spring of 1954, however, the perfect stage of one of the aquatic hyphomycetes was accidentally discovered. MATERIALS AND METHODS.-The imperfect fungus, Flagellospora penicillioides Ingold, was isolated from a collection of decomposing maple leaves found in a stream at Green Valley Falls, near Vallejo, California, in February, 1954. Several single spore isolations of this species were made and the fungus was grown in pure culture on one per cent malt agar. Most of the examinations were made on living material. In some instances paraffin sections were employed. Blocks of the fungus material were cut from the agar cultures, killed and fixed in Craf III and processed by the tertiary butyl alcohol method (Johansen, 1940). The sections were cut at 10 IL, stained with Heidenhain's iron hematoxylin and counterstained with phloxine (one per cent in 95 per cent ethyl alcohol). THE CONIDIAL STAGE.Flagellospora penicilliaides Ingold occurs on the submerged, decaying leaves and woody tissues of various angiosperms, particularly alder, willow and maple. In nature the sigmoid conidia (fig. 2, 6) are formed and released beneath the surface of the water. The conidiophores, as indicated by the specific epithet, are