A NEW FUNGUS BELONGING TO THE CLADOCHYTRIACEAE

Abstract

AS RECENTLY summarized by Berdan (1941), the family Cladochytriaceae includes eight well recognized genera. The sporangia of six of these genera dehisce following the gelatinization of the tip of the exit papillae, while the sporangia of the other two genera are operculate. In the inoperculate group are included the genera Cladochytrium (Nowakowskii, 1877), Amoebochytrium (Zopf, 1884), Physocladia (Sparrow, 1932), Catenaria (Sorokin, 1876), Mitochytridium (Dangeard, 1911), and Physoderma (Wallroth, 1833). The thalli of species of Urophlyctis (Schroeter, 1889) and of Physoderma are so much alike that most critical students of the family are more or less agreed that at present the criteria for separating these genera are superficial and inadequate. In the operculate group there are two genera, Nowakowskiella (Schroeter, 1897) with three species, and Septochytrium (Berdan, 1939), a monotypic genus. The species of Nowakowskiella at present accepted are: N. elegans (Schroeter, 1897), N. ramosum (Butler, 1907), and N. profusum (Karling, 1941a). The chytrid described as Nowakowskiella endogena Constantineanu by Domjan (1935) is probably the same as the species first described from India by Butler (1907) and just recently reported from Texas by Karling (1941b). The present paper reports a new species belonging to the Cladochytriaceae which is tentatively being placed in the genus Nowakowskiella, although the type of resting spore formation in this new species is fundamentally different from that of any of the other species of the genus. During the course of my examination of various types of bait that had been placed in water samples collected from pools and streams of eastern Illinois, I have encountered numerous chytridiaceous fungi, one of which is of particular interest. This chytrid was first isolated on cellophane as recommended bv Haskins (1939). The water samples from which it was obtained were taken near Penfield, Illinois, in the fall of 1940. It was collected again during the early summer of 1941, from Crystal Lake, Urbana, Illinois, likewise growing on cellophane bait that had been placed in a water sample. In addition to cellophane as a substratum, other materials have been used with success. Growth of the fungus on portions of grass leaves or corn seedling leaves, and on filter paper or lens paper as recommended by Couch (1939) has been quite extensive. Growth on plain agar is sparse. Unifungal cultures of this chytrid have been maintained on various types of substratum for over nine months, and observations indicate that growth on all is more or less uniform. The principal differences are produced by growth on cellophane where the cultures are less extensive, more compactly developed, have more swellings, and a larger percentage of inter-