272 Transactions British Mycological Society. 



to be seen in sections of young perithecial stromata of Xylaria 

 polymorpha, Ustulina and other fungi: the densely woven 

 covering tissue eventually turns black and forms the wall of the 

 imbedded perithecia. 



Stages of development earlier than this were somewhat in- 

 distinct, but they suggested that the coiled hypha arose from 

 two similar very transparent hyphae (fig. 38) which stain very 

 deeply with haematoxylin, one of which curved closely against 

 the other and are analogous to the simple form of gametangia 

 seen by Barker* in Monascus: at this stage the thin walled 

 covering tissue was not yet formed. 



Spore discharge extends over several weeks in detached 

 stromata and black ascospores are produced in vast quantities. 

 In the quiet atmosphere of a culture chamber long coiling threads 

 of ascospores 10 or 15 mm. or longer are extruded from the 

 mouths of the perithecia (fig. 37) which closely crowded to- 

 gether cover the whole exterior of the stromata. The coiled 

 threads look very like the threads of pycnospores which are 

 produced normally from mature pycnidia of the Sphaeropsi- 

 daceae, but they are not formed in the same way and are really 

 abnormal. If one of these threads be observed under the 

 microscope it will be seen to issue from the mouth in a jerky 

 manner and on brushing aside such a thread, asci can be seen 

 coming up to the orifice one at a time and discharging themselves 

 one after another. The discharge goes on very rapidly and the 

 ascospores from one ascus follow so closely on those from the 

 preceding one that in a auiet atmosphere they stick together 

 and a long coiling thread is produced (fig. -^j), consisting of 

 symmetrically arranged ascospores (fig. 32), for each series of 

 eight ascospores lies parallel with another series of eight and 

 the eight ascospores of each group can be seen adhering to one 

 another. Sometimes an ascus appears quite a third its length 

 above the orifice before discharging. 



Under natural conditions air currents would prevent the 

 formation of these coiled threads, for the contents of one ascus 

 would be blown away before the discharge of the next ascus 

 took place. Even in a quiet atmosphere the coiled threads of 

 ascospores are not formed if the discharge of asci is taking place 

 slowly; for by placing slips of white paper a centimeter or so 

 above the surface of a ripe sporophore, after about an hour 

 black ascospores will be seen spotting the white surface some- 

 times singly, sometimes in groups of eight. 



After the asci have been discharged, numbers of ascospores 

 remain crowded around the mouths of the perithecia ; in a damp 



* Barker. The Morphology and Development of the Ascocarp of Monascus. 

 Ann. of Bot., 1903, p. 217. 



