PERITHECIA WITH AN INTERASCICULAR PSEUDO- 

 PARENCHYMA 



F. L. Stevens 

 (with plate xxx) 



Taxonomic import is attached to the presence of paraphyses 

 between the asci in the perithecium or other ascigerous structure. 

 For this reason, as well as on purely morphological grounds, the 

 structure to be here described is of interest. 



The collection was made March 31, 1913, at Jayuda, Porto 

 Rico, on the common Maya {Bromelia pinguin). Large leaves or 

 portions of leaves were dead and rather thickly set with intensely 

 black bodies, which on microscopic examination were readily 

 revealed as perithecia, bearing abundant asci. Ordinary exam- 

 ination of material boiled in water or in potash solution, then 

 teased apart and crushed, showed no strikingly unusual features 

 about the asci, except that it was difficult to decide whether or not 

 paraphyses were really present. Material was softened in lacto- 

 phenol for two days, washed, and then imbedded in paraffin 

 through xylol, and sectioned. 



From the sections it is clearly apparent that the black, thick, 

 perithecial wall is sharply limited on its inner side, and that the 

 central area, which in most perithecia is merely a cavity or a 

 cavity partially filled with asci and paraphyses, is in this case 

 occupied by a pseudoparenchyma. The perithecial wall cells are 

 dark and thick-walled (figs. 2-3). The interascicular pseudo- 

 parenchyma is composed of thin-walled, hyaline cells, small and 

 of quite uniform size. In relatively old perithecia with mature 

 asci the spaces between and above the asci are completely filled 

 with the pseudoparenchyma. In still older perithecia the inter- 

 ascicular pseudoparenchyma is seen to break down, beginning at 

 the ostiole. An example of this is shown in fig. i. As the ostiolar 

 tissue disorganizes a mycelium penetrates down through it; whether 

 this mycelium belongs to this fungus or to another is not known 



Botanical Gazette, vol. 68] [474 



