Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 84. (Budapest 1992)

Gönczöl, J. ; Révay, Á.: Aquatic Hyphomycetes in softwater and hardwater streams of the Aggtelek National Park, NE Hungary

submerged, skeletonized beech leaves during this study. Scattered conidiophores growing on leaf veins consisting of sympodial segments, up to ca. 120 x 3-4 urn. Simple conidia straight or somewhat curved,sinuate, detached, mature conidia often with slightly inflated cells, (50) 70-90 (130) x 4.5-7.5 urn. Axis of the branched conidia straight or slightly curved, sometimes with an obtuse-angled bend at branch insertion. Two branches may grow close together from neighbouring cells and sometimes a third one at different level of the axis, 3070 x 4-7

urn. Conidial base bulbous or rarely truncate, with excentric or rarely percurrent extension up to 50 x 3-5 urn. Sometimes the basal cell with a short excentric extension appears as a special "foot cell". In foam samples considerably more simple than branched conidia were seen. This fungus was first collected in the Bükk Mts., June 1983. Since that time it has regularly been observed in hardwater streams of this mountain. Mainly skeletonized beech leaves have been found as substrate. The same characteristics in its distribution have recently been observed in the streams of the Aggtelek National Park. It appears to be absent in the streams with similar hardwater but lined by alder {Alnus glutinosa), as well as in the streams with variable hardness in andezité, Börzsöny Mts. (unpublished). Sigmoidea praelonga MARVANOVÁ, Trans. Brit, mycol. Soc. 87: 621 (1986) (Figs 5-6) - Detached conidia of this species were seen in profusion in a foam sample collected in Kecskckút-stream October, 1988 and in Patkós-stream October, 1990. Also a great number of free conidia were obtained from the water surface when decaying beech leaves were incubated for some days. Conidiophores growing on leaf veins simple or branched, septate, 30-130 x 3-5 ^m. Denticulate rachis formed on conidiogenous cell - mentioned in the description - was observed. Conidia - commonly seen at the water surface in coherent groups - straight, slightly curved, arcuate or falcate, gradually tapering distally, 50-180 (220) x 2-3(4) urn, up to 30 septate, base truncate, excentric basal extension very rarely seen, up to 25 urn long. Fragmented conidia with different length frequently seen among the undamaged free conidia. Tricladium splendens, INGOLD, Trans. Brit, mycol. Soc. 25: 385 (1942) - Profusely sporulating colonies of this fungus were seen on decaying twigs collected from Hidegviz-stream. incubated in Petri dishes without water. Many of the detached conidia appeared with unusually large sizes; axis up to 170 x 6-7 ^m, 10-20 septate, branches up to 140 x 6-7 urn. This fungus is known as a typical softwater species in streams (BARLOCHER & ROSSET 1981, GÖNCZÖL 1987) but also found commonly in different stagnant waters (ABDULLAH et al. 1981). Varicosporium delicatum IQBAL, Trans. Brit, mycol. Soc. 56: 343 (1971) (Figs 21-22) - Detached conidia of this fungus were fairly common on the water surface when decaying leaves from Hidegviz-stream, March 1991, were aerated for some days. Conidial axis up to 330 x 2-2.5 fim. cylindrical or slightly tapering distally, most often arcuate, sometimes sinuous, base truncate or obtuse-rounded, septa rare and indistinct. Primary branches mostly bilateral, 1-4, cylindrical, up to ca. 220 x 2-2.5 urn. usually arcuate, sinuous, very rarely straight, insertion very slightly constricted, the lowermost branches often in pairs, opposite. The lower branches (the first and second) often bear secondary branches. Varicosporium sp. (Fig. 23) - Free conidia of this fungus have been seen sparsely in foam samples collected from two of the hardwater streams. Conidia staurosporous, hyaline, axis cylindrical or narrowly fusoid, slightly curved, arcuate or sinuate, rarely straight, 100-200 (250) x 1.6-2.5 (3) urn, apex subulate, base slightly narrowed, scar truncate, percurrent basal extension usually present, up to 30 pm, septa up to ca. 20 indistinct. Primary branches (l-2)-3-4, alternate, usually straight and rigid, growing in different planes, insertion broad or slightly constricted, attenuate distally, apex subulate, first branches single or in pairs, opposite or nearly so, up to 130 x 1.6-2.5 urn, bearing l-(3) secondary branches: second, third and fourth branches similar to the first one but shorter and without secondary branches. Such conidia have regularly been seen in foam samples from different parts of Hungary but always found with low frequency. Never seen growing on substrate. Conidia with similar branching system are those of Polycladium equiseti Ingold. Tricladium terrestre PARK, Varicosporium gigantewn CRANE and Varicosporium delicatum IQBAL, however the first two species have more robust conidia with considerably wider elements. Vgigantewn has delicate conidia with similarly thin but much larger elements and Vdelicatum has a flexible conidial structure being distinctly different from the straight and typically rigid conidial branches of the present species. Unknown sp. 1. (Fig. 24) - This fungus was growing and sporulating on submerged decaying beech leaves collected from the Kecskekút-stream, September 1988 and June 1989. Conidiophores hyaline, single, simple or branched, 30-80 x 3-4 um. Conidiogenous cell apical or lateral, denticulate. Conidia hyaline, ampulIiform or more or less bottle shaped, straight or slightly curved, 30-60 m long, the basal part subcorneal, 3-5 urn wide, two-celled, septum often indistinct, base truncate. Distal part cylindrical or slightly tapering to the