104 



THE AMEEICAN MONTHLY 



[June, 



count of tlieir aquatic habits, and 

 also from tlie fact that they emit 

 active liagelhited spores from the 

 clavatc tips of their threads, which 

 swim freely like infusoria — they 

 were at one time associated with 

 the Algae. Mr. Berkely however 

 says : " In these lower plants tliere 

 is a duality or plurality of modes of 

 fructification. Indeed, though the 

 active spores moving about with 

 one or more lash-like appendages 

 exactly resemble the reproductive 

 bodies which are so common among 

 Algge. There is now evidence among 

 moulds, as in the genera Perono- 

 sjpora (the potato destroyer) and 

 Vystoptis^ and still more amongst 

 the Myxogastres, that there are act- 

 ive spores amongst "true fungi;" 

 further, quoting Pringshiem's defin- 

 ition of the genus Sajprolegnia^ he 

 says : " Infusorial spores formed in 

 the interior of the sporangia, and 

 immediately after their formation, 

 isolated and active without any pre- 

 vious membrane. New sporangia 

 formed by the repeated protrusion 

 of the basal membrane into the 

 old sporangium, oogonia containing 

 numerous resting spores," 



To make the history more intel- 

 ligible, Mr. Berkely describes one 

 or more species of each genus, and 

 says of Saprolegnia monoica and 

 ferax. " The first appearance is 

 that of delicate, white or greyish, 

 nearly equal, simple or slightly 

 branched threads, without any 

 joints, radiating in every direction, 

 and containing a grumus, granulat- 

 ed mass. The tips of these threads 

 gradually swell, and after a time a 

 septum is formed at the base, after 

 which the contents are collected in- 

 to little pellets, each of which at 

 length, is separated from the rest, 

 and becomes an ovate spore, which 

 escapes by a little aperture at the 

 tip, and is furnished with one or two 

 delicate thread-like appendages, by 



means of which it is able to move 

 about like an infusorial animal with 

 great rapidity. After a short time 

 motion ceases, and the spore germ- 

 inates and produces a new plant. 

 " After the sporangium is exhaust- 

 ed the septum at the base becomes 

 convex, pushes forward into the 

 vacant cavity, which it more or less 

 completely fills, and produces an- 

 other crop of spores, sometimes 

 projecting through the aperture of 

 that which was first formed. This 

 process is repeated a third or even 

 a fourth time till the powers of 

 vegetation are exhausted. Now, 

 however, a second form of fruit 

 appears, a form that has been 

 called an oogonium, because it 

 produces spores which are quies- 

 cent and dormant, for a time, like 

 eggs, and not furnished with motile 

 appendages. Lateral branches are 

 given up for their production which 

 terminate in large globose sacs, 

 which, like the sporangia, are not 

 at first separated by any septum. 

 One, however, is at length formed, 

 and the membrane becomes pierced 

 with numerous apertures." {Intel- 

 lectual Observer^ Vol. Y.) 



The above authorities show that 

 this fungus is possessed of several 

 methods of fructification, and that 

 it also produces resting-spores 

 which may retain their vitality 

 for an indefinite time. Moreover, 

 it is not strictly aquatic in its habits, 

 but can exist and propagate itself 

 out of water — in fact is amphibious 

 — it is extremely common on flies in 

 Autumn, when the insect appears to 

 be gummed to places and covered 

 with a white powdery efflorescence 

 — this is the vegetable parasite in 

 question — known when it attacks 

 the house-fly as Emjpusa Tuuscoe: but 

 certainly analagous \oo, if not iden- 

 tical with S. ferax. Mr. Berkely 

 regards it as the latter fungus. 



The fly, by the destruction of its 



