REMARKS ON THE PILOBOLIDAE 



i8i 



p. 203) that its form is a valuable aid in identifying this species. 

 In the other Piloboli, the basal swelling as a rule is rounded, turnip- 

 shaped, or oval. 



In all the species of Pilobolus, the basal swelling together with 

 the fruit-body which grows out of it may be and usually is solitary ; 

 but in some species, e.g. P. roridus (Fig. 101, F, p. 204) and P. nanus 



Fig. 89. — Pilobolus umbonatus. Gennination of spores and tlevelopnieiit of a 

 trophocj'st (which becomes the basal swelhng of a fruit-body). Culture medium, 

 cleared horse-dung agar. A : a, spores placed in culture medium ; b, c, and 

 d, two days later ; b, a spore swelling ; c, two spores putting out germ-tubes ; 

 d, a spore with a long germ-tube. B : a main hypha of a mycelium, with 

 numerous slender brandies (secondary hyphae). C : a main hypha which has 

 become swollen at 6 as a step toward the formation of a trophocyst. D : a main 

 hypha in which a local swelling has become divided by two septa, so as to form 

 a trophocyst b and two apophyses a a. Drawn by A. H. R. BuUer and E. S. 

 Dowding. Magnification : A, 350 ; B-D, 80. 



(Fig. 106, C, p. 212), two or three or possibly more basal swellings, 

 which become extended into fruit-bodies, may occur in short chains. 

 A single basal swelling in any Pilobolus species usually arises in 

 the middle of one of the stouter hyphae in an intercalary manner 

 and becomes cut off from the rest of the hypha in which it has 

 originated by two septa (Fig. 89, also Figs. 21 and 27, pp. 52 

 and 69). One or both of the adjacent portions of the hypha may 

 then become swollen to form one or two so-called apophyses (Figs. 89 

 and 90). When one examines a mature fruit-body, if only one 

 apophysis has been developed (Fig. 90, C-E ; also Figs. 27 and 101, 



