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RESEARCHES ON FUNGI 



much larger, P. longipes spores ; while the photomicrograph repro- 

 duced in Fig. 83, with the same magnification as for Fig. 82, shows 

 spores of P. umbonatus, P. Kleinii, and P. longipes in a single 

 field of view. In Fig. 83 one can readily distinguish the spores 

 of P. umbo7iatus by their ellipsoid form, paleness, and very 



small size from those of P. Kleinii which, 

 although also ellipsoid in form, are very 

 much larger and darker, and from those 

 of P. longipes (three only, to the right) 

 which are rounded-oval in form, very 

 much larger, and darker. Thus Figs. 82 

 and 83 serve to demonstrate, in respect 

 to the nature of their spores, how very 

 distinct from one another are P. umbo- 

 natus, P. Kleinii, and P. longipes. 



At room temperatures, in hanging drops 

 of cleared dung-agar, in the course of two 

 days, the spores of Pilobolus umbonatus 

 swell up greatly and put out germ- tubes 

 (Fig. 89, A, p. 181). Thereafter the germ- 

 tubes branch and develop into myceha 

 (Fig. 89, B-D) with the usual two kinds of 

 hyphae : (1) main hyphae which become 

 very thick, contain much orange-yellow 

 protoplasm, and give rise to basal swellings 

 (trophocysts) of fruit-bodies ; and (2) much 

 smaller lateral hyphae which doubtless 

 send protoplasm and other materials into 

 the main hyphae. 

 The basal swellings (trophocysts) of fruit-bodies arise as rounded 

 or oval swellings in the coarse stolon-like hyphae (Fig. 89, B-D, 

 p. 181). They may be apparently terminal at the end of a hypha 

 (Fig. 90, C-E, p. 182) or be obviously intercalary (Figs. 89, D, and 

 90, A, B). Sometimes they are dispersed at intervals along a single 

 longer hypha (Fig. 90, G). Each basal swelling gives rise to a stipe 

 and, as the stipe grows out from it, it usually becomes more or less 

 turnip-shaped (Figs. 90, C-E, and 105, C, D, and H, pp. 182 and 210). 



Fig. 84. — Pilobolus umbo- 

 natus. Large fruit-body 

 from pure culture. Mag- 

 nification, (51. 



