CHYTRIDIALES 195 



Micromyces zygogonii Dangeard 



Le Botaniste, 1 : 52, pi. 2, figs. 1-10. 1889 

 (Fig. 16 C, p. 196) 

 Synchytrium zygogonii (Dang.) Karling, Mycologia, 45: 278. 1953. 



Prosorus spherical, 11—18 (jl in diameter, with a thickened colorless 

 wall the outer surface of which is covered with numerous slender sharp 

 tapering spines 4-7.5 u. long; sorus emerging through a small pore 

 formed in the wall of the prosorus, at first spherical, 13-25 \x in diam- 

 eter, with a thin wall, at maturity becoming somewhat angular ow- 

 ing to the formation of from four to eight pyramidal truncate spo- 

 rangia with rounded bases, sporangia 6-11 \x broad by 12 \x high, with 

 from one to three small discharge papillae; zoospores spherical, ovoid 

 or fusiform, 1-2 [j. long, with a minute colorless refractive globule 

 and a fairly long flagellum, movement hopping or amoeboid; resting 

 spore spherical, about 12.5 jx in diameter, covered with somewhat 

 shorter spines than those on the sporangium, inner wall thick, brownish 

 or brownish red, germination not observed. 



Parasitic in various Conjugatae and often causing pronounced swell- 

 ing and elongation of the host cell. In Zygogonium sp., Dangeard 

 (he. cit.; 1 890-9 lc: 245, pi. 17, figs. 2-8), Spirogyra quadrata, Denis 

 (1926: 14, fig. I, 2), France; Zygogonium sp., de Wildeman (1891: 

 172), Belgium; Mougeotia sp., Petersen (1910: 556, fig. 27c), Den- 

 mark; Conjugatae, Pringsheim (1895), Minden (1915:281), Netrium 

 sp., Mougeotia sp., Schulz (1922: fig. 91 ; 1923: figs. 10-11), M. scalar is, 

 Heidt (1937:204, figs. 1-8), Spirogyra mirabilis, Rieth (1950a: 510; 

 1950b: 264, figs. 1-10), Mougeotia sp., Rieth (1956a: 35, fig. 16), 

 Germany; Mougeotia sp., Huber-Pestalozzi (1931:88, pi. 3, figs. 

 1-23), Switzerland; Mougeotia sp., Zygogonium sp., Couch (1937: 

 595, figs. 1-8), Mougeotia sp., Sparrow (1943: 137), Spirogyra sp., 

 Sparrow (1952d: 760), United States; Spirogyra sp., Canter (1949c: 

 82, figs. 8 a-i, 9, 1 1 a-b, 12a-g; pi. 10, figs. 1-3), Great Britain. 



Huber-Pestalozzi (be. cit.) and Heidt (loc. cit.) give references to 

 the older algological literature containing descriptions of "astero- 

 spheres." (See also Thwaites, 1846-47; Shadbolt, 1852; Smith, 1853; 

 de Bary, 1858; Reinsch, 1879; Pringsheim, 1895.) 



De Wildeman (1900a: 1) has given the name Micromyces mesocarpi 



