Fungi of Enewetak Atoll 



Chapter 2 



PAUL H. DUNN* AND DON REYNOLDSf 



'Riverside Fire Laboratorii. USDA Forest Service 

 Riverside, California 92507 

 fNatural Historii Museum, Los Angeles Counfy 

 Los Angeles, California 90007 



INTRODUCTION 



The microfungi of Enewetak Atoll are typical tropical 

 forms and are not restricted to that atoll. Because of the 

 extreme isolation of Enewetak, however, it seems likely 

 that the fungi there are indigenous to the atoll and are not 

 introductions by man. Whether the origin is terrestrial or 

 from the beaches remains a question. 



The first study of microfungi on Enewetak (Sparrow, 

 1948) isolated unicellular chytrids of three different fami- 

 lies from soil samples (Table 1), but no filamentous chy- 



trids or Oomycetes were isolated. An extensive study 

 (Dunn, 1973) isolated 101 specimens from the beaches of 

 Enewetak. An additional eight newly recorded taxa are 

 listed in Table 1. The specimens were isolated by the 

 Warcup plating method (Warcup, 1950), which established 

 only that viable propagules were present. Whether the fun- 

 gal propagules of the Enewetak beaches are dormant or 

 active was not defined. Fungal propagules have been 

 preserved for long periods when stored in distilled water 

 (Campbell and Stewart, 1980). It can be assumed, there- 

 fore, that nutrient-poor seawater could provide a habitat in 

 which those propagules that tolerate salinity could remain 

 viable. 



Reports from the atoll beaches (Dunn, 1973; Steele, 

 1967) are based on isolations from enrichment culture. 

 Marine fungi have been defined as those observed growing 

 on a substrate in a marine habitat (Kohlmeycr and 



TABLE 1 

 Checklist of Enewetak Atoll Fungi 



Kingdom MYCETEAE 



Class CHYTRIDIOMYCETINA 

 Order CHYTRIDIALES 

 Family OLPIDIACEAE 



Olpidium rhizophl\/ctidis Sparrow: Sparrow, 1948. 

 Family PHLYCTIDIACEAE 



Rhizoph^dium marshallense Sparrow: Sparrow, 1948. 

 Family RHIZIDIACEAE 



Rhizophlvctis rosea (DeBary and Woronin) Fischer: Sparrow, 1948. 

 Class ZYGOMYCOTINA 

 Order MUCORALES 



Family PIPTOCEPHALIDACEAE 



' Svncephalastrun racemosum Cohn ex Schroter, 1886. 

 Family THAMNIDIACEAE 



' Helicosfylum ghrneratum (van Tieghem and Le Monnier) van Tieghem, 1876 

 Family MUCORACEAE 



Absidia corymbifera (Cohn) Saccardo and Trotter: Dunn, 1973. 

 Mucor sp.: Dunn, 1973. 

 Rhizopus nigricans Ehrenberg: Dunn, 1973. 

 Order ENTOMOPHTHORALES 

 Family ENTOMOPHTHORACEAE 

 Conidiobolus sp.: Dunn, 1973. 



'New Enewetak Atoll record. 



(This table continued on next page.) 



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