SPOROBOLOMYCES 183 



yeast cell ; and other observations go to show that the spores are 

 discharged from their sterigmata to a vertical or horizontal dis- 

 tance of about 0-1 mm., i.e. the same distance as observed by 

 Kluyver and van Niel x for S. salmonicolor and the same distance 

 as observed by myself 2 for Psalliota campestris and many other 

 Hymenomy cetes . 



There can be no doubt that the production and liberation of a spore 

 in Sporobolomyces roseus, as so far described, in all essentials exactly 

 resembles the production and liberation of a basidiospore on one of 

 the sterigmata of a basidium in the Hymenomycetes, the Uredineae, 

 and the genus Tilletia. In this connexion the reader should compare 

 with Fig. 90, nos. 1-8, the illustrations for the production and 

 liberation of spores given for Calocera cornea 3 and Psalliota 

 campestris 4 in Volume II, for Puccinia graminis 5 and Endophyllum 

 Euphorbiae-sylvaticae 6 in Volume III, and for Tilletia tritici 7 in this 

 Volume V. 



Abnormal Drop-excretion. — Normally, the drop which is ex- 

 creted from the hilum of a spore of Sporobolomyces roseus just before 

 the spore is discharged attains a diameter about equal to that of the 

 spore (Fig. 90, nos. 7, 11, and 15). However, under unfavourable 

 cultural conditions it sometimes happens that the drop, after attain- 

 ing the usual maximum size (Fig. 91, 6), continues to grow, runs up 

 the spore (c), and finally envelops the spore completely (d). This 

 abnormally large drop within a minute or two enlarges so much that 

 its volume much exceeds that of the plant which has excreted it. 

 Its maximum size is indicated in Fig. 91, d. Whenever abnormal 

 drop-excretion like that just described takes place, the spore is not 

 discharged. Similar observations were made by Kluyver and van 

 Niel 8 in the course of their investigations on Sporobolomyces 

 salmonicolor. 



1 A. J. Kluyver and C. B. van Niel, loc. cit., p. 13. 



2 These Researches, Vol. I, 1909, p. 142. Cf. Fig. 65, p. 186. 



3 These Researches, Vol. II, 1922, p. 7. 



4 Ibid., p. 12. 



5 These Researches, Vol. Ill, 1924, pp. 503, 505. 



6 Ibid., p. 511. 



7 Vide infra, Fig. 108, p. 222, and Fig. 114, p. 232. 



8 A.J. Kluyver and C. B. van Niel, loc. cit., p. 16, Taf. I, Fig. 12. 



