410 MARINE FUNGI 



from attempts to isolate in culture fungi obtained in samples of 

 mud from the ocean bottom at various depths. This second pro- 

 cedure has yielded no typically marine species, all isolates being 

 common species of Aspergillus, Penicillium, and similar genera 

 [Sparrow (1937)1. By direct examination of decaying algae, 

 largely through the work of Sutherland (1916), however, a num- 

 ber of species have been identified. These include Alternaria 

 maritima, Blodgettia confervoides, Cladosporium algarnm, Cerco- 

 spora salinia, Diplodina I ami n avian a, Epicocann viavitivnmi, Ma- 

 crosporium laminarium, Monosporium maritimum, Sporotrichinu 

 viarit'nmnn, and Steviphyliinn codii. Feldmann (1940) described 

 Macro phoma gyumogongri as a parasite on Gyrnnogongrus norve- 

 gicns. 



MARINE SLIME MOLDS 



The most important among the several species of marine slime 

 molds is that within diseased leaves of Zostera marina. It has, with 

 uncertainty, been identified as Labyrinthula macrocystis, an or- 

 ganism consisting of net-like aggregates of individuals connected 

 by pseudopodia. The individuals are spindle-shaped and glide 

 along this interconnecting pseudopodial network. 



Affected leaves of Zostera bear dark streaks and splotches. 

 Often the cuticle and cortex of the stems are also irregularly 

 spotted with dark brown or black areas. Affected leaves slough 

 off; the stem may persist for a year or two and form new shoots, 

 but eventually the reserve food is exhausted, the plants waste 

 away, and the roots decompose. 



Among those who have studied this eel-grass disease are Peter- 

 sen (1935), Renn (1936, 1937), and Young (1938). Accord has 

 not been reached concerning its etiology, but Renn and Young 

 interpret their evidence as showing that Labryinthula is the patho- 

 genic agent. Among the causes assigned by others are the pyre- 

 nomycete Ophiobohis halimus, bacteria, unfavorable light, un- 

 favorable temperature, and accumulation of industrial wastes and 

 oil. 



IMPLICATIONS 



It is of more than passing interest to note that, with the excep- 

 tion of the disease on Zostera, fungus diseases of marine plants 

 sufficiently abundant and widespread to be regarded as epidemics 



