RESEARCHES ON FUNGI 



of Pilobolus not only raises the sporangium above the substratum 

 but is also adapted for shooting the sporangium away to a consider- 

 able distance. With this difference of function is associated a very 

 marked difference in the structure of the two sporangiophores, that 

 of Pilobolus being morphologically much more highly speciahsed 

 than that of Mucor. 



Pilobolus, owing to its very common occurrence, the beauty of 

 its form, its unique subsporangial swelling, its very pronounced 



heliotropism, the 

 beads of water with 

 which its sporangio- 

 phore is usually orna- 

 mented, and the great 

 distance to which its 

 sporangium is dis- 

 charged, has attracted 

 the attention of my- 

 cologists for more 

 than two centuries, 

 and to-day it is de- 

 scribed in many text- 

 books of Botany. As 

 a contribution to our 

 knowledge of a fungus 

 which is of such per- 

 ennial interest, there 

 will be presented : in this Chapter a historical review of the 

 literature on Pilobolus ; in Chapter II an account of the author's 

 researches on Pilobolus, of which a brief report ^ was made in 

 1921 ; in Chapter III a description of a new species, Pilobolus 

 umbonatus ; and in Chapter IV a taxonoraic description of all 

 the known species of Pilobolus, drawn up by Mr. W. B. Grove. 

 In Chapter II, from the point of view of the organism as a 

 whole, it will be shown : (1) that the subsporangial swelling, in 

 addition to acting as part of a squirting apparatus, has the function 



1 A. H. R. Buller, " Upon the Ocellus Function of the Subsporangial Swelling of 

 Pilobolus," Trans. Brit. Myc. Soc, Vol. VII, 1921, pp. 61-64. 



Fig. 1 . — Pilobolus longipes. A group of sporangiophores 

 which came up spontaneously on horse dung in the 

 laboratory at Winnipeg. They were all directed 

 toward the source of brightest daylight. Natural 

 size. 



