30 British UredinecB aiid UstilaginecE. 



the action of caustic potash ; and they are much less 

 easily observed when the spores are examined in water 

 than when they are seen dry. This is equally true of the 

 aecidiospores. 



In the endospore are two or more openings (germ- 

 pores, oscules) through which the germ-tubes emerge when 

 the spores germinate. They can sometimes be made out 

 pretty clearly in perfectly ripe spores, but not often. There 

 is no difficulty, however, in observing them in those spores 

 in which the process of germination has commenced. In 

 the globose uredospores they are arranged in a circle 

 round the equator ; in the oval spores, also midway 

 between the poles. Whether it be correct to regard them 

 as openings is doubtful ; they would be more correctly 

 described as thin places, which become holes. The number 

 of germ-pores varies in different species ; they are never 

 less than two. Their variation in number and position 

 is but slight: thus De Bary* gives for U. linearis, four; 

 U. fabcs,'\ three ; U. phaseoliX two ; and U. sitaveolens^ 

 three. 



Recently De Bary || has stated that in the uredospores 

 of Puccinia and Uromyces the germ-pores are sharply 

 defined, circular holes in the endospore, closed externally 

 by the exospore ; but this hardly accords with my observa- 

 tions. The spore-bed continues to produce uredospores for 

 some considerable time ; at length it ceases to do so. If 

 it be examined in this condition it will be found to consist 

 of little else than barren basidia, with here and there one 

 bearing a spore. The uredospores vary in colour ; most 

 are some shade of orange, many are brown. De Bary IT 

 has pointed out that in those species with brown spores 

 the contents are colourless, e.g. in U. pJiaseoli, nmiicisy 



* De Bary, " Brandpilze," p. 33. t De Bary, "Champ, paras.," p. 74. 

 % Ibid., p. 76. § De Bary, "Brandpilze," p. 33. 



II De Bary, " Vegl.," p. 109. t De Bary, "Brandpilze," p. 31. 



