244 RESEARCHES ON FUNGI 



A single paraphysis (Fig. 119, d) is a thin, much branched, 

 septate structure, the cells of which contain deep-red particles. 

 It is these particles which give to the hymenium as a whole its fine 

 scarlet colour. The paraphyses constitute more than one-half of 

 the hymenium and, as shown in Figs. 120, A, and 121, A, they he 

 between the asci and isolate them from one another. The branches 

 of the same paraphysis or of adjacent paraphyses are closely packed 

 together and become anastomosed with one another. Although the 

 paraphyses tightly ensheathe each individual ascus, their walls and 

 the ascus-wall, where they come into contact, are never fused 

 together but are free to move over one another. This freedom is 

 important, for it permits a young ascus to grow in length and an 

 exploding ascus to contract in length and slide downwards in the 

 hymenium between the paraphyses without any serious disturbance 

 to the hymenium as a whole {cf. A and B in Fig. 120). With iodine 

 the red particles in the paraphysal cells turn green. 



The ascus is a long thin cylinder with a narrower, often undulating 

 base and a straight shaft. In Fig. 119 there are shown : at a an 

 almost ripe ascus which as yet does not protrude beyond the general 

 level of the hymenium as determined by the tips of the paraphyses d ; 

 at 6 a mature, fully protuberant ascus ; and at c an ascus just after 

 it has exploded and shot away its spores. In both a and b the cell- 

 walls are very thin and are hned internally by an equally thin layer 

 of cytoplasm. This cytoplasmic layer encloses a single large central 

 vacuole, filled with colourless cell-sap, and eight spores. The spores 

 are situated in the upper end of each ascus. They adhere to one 

 another and to the top of the ascus, so that they cannot fall down 

 to the bottom of the vacuole, from which position they could 

 not be discharged when the ascus exploded. It seems probable 

 that they are held together and are attached to the ascus-apex 

 by cytoplasm. In any case the adhesive substance is weak ; 

 for, when an ascus explodes, the top spore is freed from the 

 top of the ascus and all eight spores are separated from one 

 another. 



The eight spores in each ascus (Fig. 119, a, b) are long and oval 

 or almost fusiform, and they all slope obliquely in the same direc- 

 tion. The upper end of the top spore rests against the operculum 



