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During the past year, two very interesting rusts of the family Melampsoraceae have come to the writer's attention. The first of these, upon Nyssa aquatica, has remained in the form genus Uredo since its description in I890 by Ellis and Tracy under the name of Uredo Nyssae. While preparing the manuscript of this species for the North American Flora, the writer was fortunate in discovering the telia. A study of this stage shows that the species can not be placed in any established genus and in consequence the following genus is proposed.

Records and observations of subfamily Pucciniastreae (Melampsoraceae) and related imperfect rust fungi are reported here, with special attention to Melampsorella and description of a Uredo on Asplenium. G. B. Cummins (Purdue), C. R. Benjamin (National Fungus Collec? tions), P. C. Lightle (Forest Service, Rocky Mountain Station), A. H. Holmgren (Utah State), R. McVaugh (Michigan), L. Bonar (Cali? fornia), W. E. Booth (Montana State College), C. C. Gordon (Montana State University), and D. B. Lellinger (Smithsonian Inst.) helped by providing information or collections. Specimens are in the National Fungus Collections (BPI) or at Berkeley (University of California), and duplicates of my collections are in the Logan herbarium of the Intermountain Station. Collections prefixed "60" and "61" were made while I was with the Rocky Mountain Station of the Forest Service, and are filed also at Fort Collins. Spore measurements are based on 20 to 50 spores, depending upon homogeneity of samples.

Among the rusts (Uredinales) the family Melampsoraceae is of great interest because of the variety of host relationships and the diversity of forms exhibited by its various members. Attempts have been made to give expression to natural affinities among genera of the family, but, unfortunately, many of these attempts have been based upon superficial observations or upon incorrect interpretations of certain morphological characters. It is apparent, therefore, that a more thorough investigation of these rusts should precede further endeavors to express natural relationships in a phylogenetic classification or otherwise. In a recent paper (4), attention was directed to the uredinial stage of one subfamily of the Melampsoraceae, namely, the Pucciniastreae, and it was concluded (contrary to certain earlier reports) that the uredinia of representative forms of this sub? family are strikingly similar in their mode of development. The present communication deals with a member of each of two other subfamilies of the Melampsoraceae, namely, the Cronartieae and the Melampsoreae, and the main conclusion reached is that the uredinia of these species develop in essentially the same manner as in the Pucciniastreae. In connection with the follow? ing descriptions of Cronartium Comandrae and Melampsora Medusae, it has been considered unnecessary to provide illustrations, because very similar stages in development are fully figured in an earlier paper (4).