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RESEARCHES ON FUNGI 



a young hymenium taken from the side of a fruit-body, the outer 

 ends of the paraphyses are all turned toward the light. This 

 heliotropic bending of the paraphyses facilitates the heliotropic 

 bending of the asci ; and it may therefore be said that in A. vesiculosa 

 the paraphyses prepare a way for the asci which come after them 

 and eventually push out beyond them. At first the young asci are 

 straight, as shown in Fig. 145 ; but, as soon as they become about 

 half-grown in length, they respond to the stimulus of light and, in 



Fig. 144. — Diagram of the construction of a sessile apothecium of one of the 

 Discomycetes. Marginal growth is taking place. The marginal hj'phae 

 all around the periphery of the disc are developing sympodially, giving 

 rise to paraphyses above and cortical cells below. It will be seen that, 

 at the margin of the hymenium, the paraphy.ses are formed first and that 

 afterwards asci grow up between tliem. Drawn by E. J. H. Corner 

 (Trans. Brit. Myc. Soc, Vol. XIV, 1929). 



so doing, make their way between the curved paraphyses without 

 disarranging them (c/. Fig. 140, p. 293). 



The paraphyses, at first, are only about 3 (i. in diameter and are 

 quite cylindrical (Fig. 145) ; but, as the fruit-body ripens, they 

 undergo a considerable change in form. By the time the first asci 

 are ripening or are ready for spore-discharge, their terminal cell 

 has become somewhat clavate and their shaft-cells have increased 

 considerably in diameter (cf. Fig. 140, p. 293). Finally, by the 

 time the fruit-body has become fully expanded and all the asci 

 have ripened and some or many have burst, their terminal cell may 

 have become markedly clavate and their shaft-cells have become 



