Fungous Flora of the Soil 467 



diclinous origin, sometimes even from the oogonial branch ; oospores single, 

 globular, concentric, 20-2 2/x in diameter. 



Hab. Soil saproph^'te, parasite on beet (Busse, Peters, Ulrich) and 

 on decaying insects in water. 



Pythium de Baryanum Hesse, Inaug. Diss. Halle, pis. 1-2. 1874. 

 Butler, Mem. Dept. Agr. India No. 5, i: 86-91. 1907. 



IMycelium rather coarse, intra- and extramatrical. Hyphae large, 

 branching irregular and free, septate in old cultures. Sporangia spherical 

 or oval, chiefly extramatrical, terminal and intercalary; supporting hyphse 

 usually emptied of their contents for a variable distance below the spo- 

 rangium, and separated by septa from the full part of the hyphse and from 

 the sporangium. Tube of discharge lateral, about the diameter of the 

 sporangium in length. Proliferation is absent; conidia usually numerous, 

 intra- and extramatrical, 15-25^ in diameter, round oval, or somewhat 

 irregular in shape and size in old cultures, may germinate at once but 

 more usually do so after a short rest if transferred into fresh water. 

 Oogonia usually numerous, intra- and extramatrical, sometimes formed 

 very early in culture, 20-2 5/x in diameter, spherical, terminal or intercalary. 

 Antheridia up to 3 in number, from the same or another hypha as the 

 oogonium, often formed close below the latter and not seldom hypogonal. 

 Oospores 14-18^1 in diameter", not filling the oogonium, spherical, smooth, 

 germinating after a rest of some months by a branching hypha. 



Hab. Saprophytic in soil, Europe, United States, Butler; Europe, Busse, 

 Peters, and Ulrich. Parasitic on a number of seedling phanerogams 

 and on prothallia of ferns and Equisetimi, Europe, United States. 



Pythium intermedium de Bary, Bot. Ztg. 39: 554. pi. 5, figs. 14-16. 

 1881. Butler, Mem. Dept. Agr. India No. 5, i: 6 and 96-99. 1907. 



Syn. Artotrogus intermedius (de Bary) Atk., New York (Cornell) Agr. Expt. Sta. 

 Bui. 94: 247. pi. 2, figs. 10-25. 1895. 



Mycelium extra- and intramatrical, forming a regular fine haze around 

 the substratum in water culture. Hyphag very numerous, up to 6/i thick, 

 regular, without intercalary swellings; branching often at right angles, 

 sometimes dichotomous, more usually lateral. In old cultures septa, 

 with a distinct double contour, are not uncommon. The tips of all 

 free branches usually end in spores. They measure 18-24/i in diameter 

 and are normally arranged in chains. When ripe they fall off readily 

 and can germinate immediately in fresh water. (For manner of formation 

 and position of spores see Butler.) Spores in the chain spherical or pear- 

 shaped. These may germinate as sporangia or as conidia. In young 

 cultures, large numbers of sporangia occur and discharge zoospores on 

 addition of fresh water. In older ones the conidia are the organs chiefly 

 found. The tube of discharge is always short, about one half the diameter 



