250 



STRUCTURAL BOTANY 



small flask-shaped receptacles called spermogonia, (Fig. 



102), each of which, in our type and its near allies, is 

 sunk in a wart-like elevation of 

 the thallus. The interior of the 

 spermogonium is occupied by a 

 net- work consisting of sterile cells 

 and fertile lasidia. From the 

 latter, excessively minute cells, 

 budded 



the spermatia, are 



off 



FIG. lQ2.Physcia put 



veruUnta. Longitudinal (Fig. 103). The nature of these 



spermatia has been much dis- 

 elevation of the cortex, puted ; there appears to be 



Magnified. (After Darbi- . , ' ., c -,. 



shire.) weighty evidence for regarding 



them, at least in certain cases, 

 as the male cells of the Lichen. 



FIG. 103. Physcia pulvcrulenta. Portion 

 of the tissue inside a spermogonium, 

 showing the groups of sterile cells (G), 

 and the basidia bearing spermatia. 

 Highly magnified. (After Darbishire.) 



In most species investigated the apothecium has been 

 found to arise from a special cellular filament, the carpo- 



