PERISPORIALES 



209 



mucronate hyphopodium (Fig. 132, 4) corresponds to the simple hypho- 

 podia of Balladyna; they are mostly formed as two single, opposed cells 

 which may be regarded as short, unicellular branches. Possibly they 

 form the appressoria; their ontogeny is still unknown. The capitate 

 hyphopodia or stigmatopodia (Fig. 132, 3) are generally darker than the 

 mucronate hyphopodia and alternately branched; thus one cell forms 

 one of these branches to the right, the next cell forms one to the left, the 

 next to the right, etc. Generally the stigmatopodia are inclined 

 obliquely forward toward the growing tip. They generally consist of 

 two cells, a stipe cell and a spherical terminal cell, the stigmatocyst. 



Fig. 133. — Parodiopsis Perae. 1. Hyphae with setae and young conidia, C. Parodi- 

 opsis melioloides. 2. Section through the lower surface of a leaf with setaceous mat and 

 immature perithecium. (1 X 250; 2 X 100; after Arnaud, 1918, 1923.) 



They are slightly reminiscent of the appressoria of the Erysiphaceae and 

 possibly are related to haustoria. 



The stigmatocyst may develop the perithecia; it swells and divides 

 into two cells, the terminal cell developing slowly to form the core of 

 ascogenous tissue while the basal cell produces the perithecium in a 

 manner suggestive of that in the Laboulbeniales (Ryan, 1926). 



Thus the perithecia, as in Balladyna, arise from a single branch of a 

 hypha. At maturity they are spherical and resemble the Erysiphaceae; 

 they consist of a dark, often carbonaceous rind, and a hyaline ground 

 tissue, the rosette of asci. The brown rind is generally homogeneous, 

 as in Balladyna and the Erysiphaceae; occasionally, as a step in the 



