Formation of Tcleutospojxs of UstilaginecE. 6^ 



entering the ovary through the flower-stalk, sends its 

 hyphae through the funiculus into the ovule, which becomes 

 permeated by densely interwoven hyphae. The micro- 

 pylar end of the integuments alone escapes and remains, as 

 a cap on the top of the diseased ovule, for some time, 



Fig. ^.—Sphacelotheca hydroplperis (Schum.) A, Ovary and perianth of Polygonum 

 hydropiper affected with 5". hydropiperis. B, The same more advanced, showing the micro- 

 pylar cap {c). C, Section of ovary and perianth at an early stage ; g; the style ; o, the 

 integument of the micropylar end of the ovule ; /, wall of the ovary; /, the perianth. The 

 spore-formation is seen to be commencing above, and the rudimentary cohimella is visible. 

 D, Section of a more advanced ovary, showing the walls of the receptacle and the columella 

 (c). Slightly magnified. (De Barj'.) 



but eventually falls off The hyphae develop partly into 

 spores and partly into the receptacle. The latter consists 

 of a thick external case with a central columella. The 

 cells of which it is composed are but loosely compacted, 

 colourless, and about the size of the spores. The least 

 injury fractures this case and allows the escape of the 



