The Rust Fungi ( Uredinales ) of Hawaii 1

The fungi of Hawaii were documented by F. L. Stevens and other workers early in the 1900s. Since about 1925, however, little formal attention has been given Hawaiian rust fungi . This is the first study devoted exclusively to Hawaiian Uredinales as a group. During recent years we have contributed a number of rust specimens to the Herbarium Pacificum, Bernice P. Bishop Museum (BISH), which includes the most complete collection of Hawaiian fungi . Our contributions, together with the earlier deposits, supplemented by the Animal and Plant Health Inspection Service, U.S. Department of Agriculture, reference collection at Honolulu International Airport (HONQ) and information from the USDA National Fungus Collections (BPI), provided the basis for this study . The fungus collection of the Department of Botany, University of Hawaii at Manoa (HONO), was also examined. We recognize 74 species, 9 of which are endemic , and an additional 13 occur on native host s. As with many rusts in tropical areas , most species reported here are less than macrocyclic or are represented only by uredinial and /or telial states and do not utilize alternate hosts . SINCE THE PUBLICATION OF Hawaiian Fungi by F. L. Stevens in 1925 (Stevens 1925), little attention has been given to the Uredinales of Hawaii. At the time of Stevens' publication, 39 species of rust fungi were recognized from Hawaii , most of which were known to have been recent introductions on crops, ornamentals, or weeds from elsewhere. Stevens noted the relatively scant number of rusts in Hawaii as compared to other insular localities, such as Puerto Rico, with which he was familiar. He attributed this overall scarcity, as well as the scarcity of aecial forms, to the remoteness of the Hawaiian archipelago from continental landmasses. Stevens concluded that rusts did not come to Hawaii windborne, but primarily had been introduced with their hosts . Introduction of alternatehostsof heteroecious .rusts,_usually plants totally unrelated to the primary hosts , would be coincidental, and appears not to 1 Manuscript accepted 3 March 1988. 2Cooperative Park Studies Unit, National Park Service, University of Hawaii at Manoa, Department of Botany, Honolulu, Hawaii 96822 . 3 North Carol ina State University, Department of Plant Path ology, Raleigh , North Carolina 27695. 41 have occurred often . In mild climates, rust fungi are capable of surviving indefinitely in the uredinial state and do not require alternate hosts. Stevens (1925: 176) recognized 7 endemic rust species from Hawaii . Each of the following, with one exception (Pu ccinia oahuensis) , was reported on an endemic host : Puc cinia oahuensis E. & E. on Syntherisma pruriens (Trin .) Arth. Puccinia velata (E. & E.) Arth. on Euphorbia multiformis H. & A. Pucciniastrum wikstroemiae Arth. in Stevens on Wikstroemia uva-ursi Gray Uredo hawaiiensis Arth . in Stevens on Carex oahuensis C. A. Mey. ex Hbd. Uredo stevensii Arth. in Stevens on Euphorbia clusiaefolia H. & A. Uromyces alyxiae Arth . in Stevens on Alyxia : olivaeformis Gaud. Uromyces koae Arth. in Stevens on A cacia koa Gray An additional species, Puccinia polygon iamphibii Pers . was also designated endemic. However, this rust is well know n elsewhere (Arthur 1962). Of the above rusts recognized by Stevens as i i i , l. , .