VARIOUS OBSERVATIONS 



PIG. 19. Lactarius piperatus parasitised by Bypomyces lactiflvorum. A, a small 

 parasitised fruit-body of L. piperatus: its gills have not been developed, owing 

 to the attack of the Hypomyces ; the under side of the pileus is thickly dotted 

 with the red perithecia ; on the right a cloud of ascospores shot out of the 

 perithecia is being carried off by the wind, and on the left, as indicated by the 

 arrows, two asci have just discharged their ascospores. B, one square millimetre 

 of the under surface of the pileus enlarged, showing the protruding perithecial 

 necks. 0, a block of tissue from the under side of the pileus, showing the cavities 

 of three perithecia containing ripening asci. D, a semi-diagrammatic section 

 through a perithecium, showing asci ripening their spores and the narrow peri- 

 thecial neck lined by hairs. E, the neck of a perithecium seen from above at the 

 moment before an ascus is discharged : small hairs cover the mouth, and completely 

 hide the end of the ascus about to explode. F, a diagram showing a vertical 

 section through a perithecium and a few of the asci : a, an ascus, after elongation, 

 in the firing position ; 6, another ascus elongating and preparing to take the place 

 of a ; c, an ascus before elongation. Gt, an ascus before elongation, showing the 

 eight spores. H, an ascus after elongation. I, two spores, isolated. J, a block 

 of tissue from the under side of the pileus so placed that the perithecia are directed 

 horizontally ; the two arrows indicate the sporabolic trajectories of the spores in 

 still air, the shorter arrow showing the average distance to which a spore is 

 projected and the longer one the maximum distance. K, a block of tissue 

 from the under side of the pileus, which after isolation has been allowed to dry 

 rapidly : several asci have been extruded bodily through the narrow perithecial 

 necks. Magnifications: A, natural size ; B, 11 ; C, 38; D, E, and F, about 67; 

 G and H, 293 ; I, 462 ; J, natural size ; K, about 6. 



