8o RESEARCHES ON FUNGI 



gelatinous ring and the surface of the cover-glass ; No. 8, a fragment 

 of the peripheral paler part of the cap-like portion of the sporangium- 

 wall (No. 3) ; and No. 9, a narrow band of sporangium-wall attached 

 to the rim of the columella. 



The somewhat brittle, paler, radiately split, outer portion of the 

 sporangial wall of a discharged sporangium (No. 3 in Figs. 33, 34, 

 and 35) may be conveniently referred to as the fringe of the spor- 

 angium. It is to be noted in a dried-up discharged sporangium 

 that the pale fringe rests directly on the film of jelly and that the 



Fig. 36. — Pilobolus longipes. Photomicrograph of a discharged spor- 

 angium which has been rubbed laterally in water under a cover- 

 glass : w, a mass of orange-red spores pressed out from under the 

 black sporangium-wall ; s, single spores ; in the centre the isolated 

 cap -shaped columella consisting of apeak a, a brim h, and a marginal 

 band (part of the sporangial wall) c. Magnification, 105. 



covering of the spores and their protection from hght-rays, etc., is 

 restricted to that part of the sporangium-wall which is very tough 

 and intenselv black. 



Cohn,^ in 1851, thought that, when a Pilobolus gun is discharged, 

 the wall of the columella does not travel with the sporangium but 

 remains behind upon the top of the subsporangial swelling ; but 

 this view was shown to be erroneous by Coemans ^ in 1861. That, 

 normally, the columella remains attached to the sporangium when 

 this is discharged can be readily proved by breaking up a dis- 



1 Ferdinand Cohn, " Die Entwicklungsgescliichte des Pilobolus crj^stallinus," 

 Nova Acta Cues. Leop., Bd. XXIII, 1851, pp. 516-517, Taf. LII, Figs. 12, 13. 



2 E. Coemans, loc. cit., pp. 42-43, Plate II, Fig. 8. 



