SUMMARYTwo chytridiaceous fungi were found in the neuston of a Florida lake. Both parasitized living pine pollen grains dropped in the water.Phlyctochytrium macrosporumwas characterized by having apophysate sporangia bearing one or more hemispherical protrusions, empty at maturity, and a small number of large (10–15 yum in diam) zoospores.Sporophlyctidium neustonicumforms in its epibiotic or stalked sporangia, spherical aplanospores which after discharge produce long straight setae, one of which makes contact with a pollen grain and enters it. The attached aplanospore then enlarges into a sporangium. Resting spores were also found but their germination was not seen. No sexuality appeared to be present.