SAPROLEGXIA 67 



EUROPEAN SPECIES NOT VET RECOGNIZED IX AMI:RICA. 



Saprolegnia rhaetica Maurizio. Flora oder Allgemeine Botanischc Zeit- 

 ung 79: 109, pi. 3, figs. 1-16, and pi. 4, figs. 1-4. 1894. 



This species is apparently near S. tonilosa and possibly the same. 

 The next species {S. variahilis) also can scarcely he separated from these 

 by the description. From 5. tonilosa and Isoachlya londoides this 

 series differs most obviously in the reputed absence of antheridia. Mau- 

 rizio's description follows: 



"Turf not very thick, up to 1.5 cm. long, with straight, slender, 

 fragile and uniiranchetl filaments. Sporangia apical, seldom intercalary. 

 Primary sporangia small, clavate, producing later through-growths of 

 varying lengths which usually tilt back over the empty cases and take a 

 variety of forms. 



"The fungus forms gemmae ['conidia' is the word used here and 

 below], which may be arranged in rows or as rolls and screws. There 

 are also complicated arrangements of gemmae in no definable system. 

 In the empty sporangia gemmae may form by constriction (usually) 

 or by cross division in basipetal succession. Corresponding to this 

 great variation in the gemmae noted is a similar variation in the gem- 

 mae found inside the empty sporangia. If the conidia are formed by 

 abstriction at the ends of hyphae the single cross walls, which for some 

 time are common to two gemmae, finally separate into two thin lamellae, 

 one of which surrounds the conidia, the other forming a connecting 

 sheath. By such a sheath are connected often a number of gemmae 

 in a row. After some time the connections between the gemmae break 

 down and the single gemmae lie free in the water by hundreds. 



"There are gradations between sporangia and gemmae in that a 

 part of the gemmae become sporangia. Also a part of the gemmae 

 may become oogonia. The formation and emptying of the zoospores 

 is the same in the sporangia and the gemmae. The spores swim more 

 than one-half hour. The small oogonia are mostly spherical, and when 

 apical and intercalary somewhat elongated. When they develop from 

 gemmae they stand in rows and may develop in the same row with spor- 

 angia, otherwise they are arranged in clusters on short stalks. Their 

 diameter is 48-61.5'^. Wall is thin, colorless, then yellowish and has 2, 

 seldom 3, pits. From the wall below the oogonium there generally 

 grows up into the oogonium a protuberance that may remain hollow or 

 may be closed with a cellulose plug. These growths are not antheridia, 

 which in this species are not present and were not even seen. Oospores 

 up to 12 in number, but mostly one to five. They have only a moder- 

 ately thick membrane and a centric structure. Their diameter varies 

 between 19 and 27.551. Germination not seen." 



Saprolegnia variabilis Minden. Krypt. Flora Mark B. 5: 524. 1912. 



"Turf thick, formed of rather thin, slender, little branched or simple 

 threads 22-27J. thick. Primary sporangia variable in size, sj^indle, or 



