30 British Uvedinee and Ustilaginee. 
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 
zecidiospores. 
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. fabe,t three; U. phaseolit two; and U. suaveolens,§ 
three. 
Recently De Bary'l| 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 1 
has pointed out that in those species with brown spores 
the contents are colourless, eg. in U. phaseoli, rumicts, 
* De Bary, ‘‘ Brandpilze,” p. 33. t De Bary, ‘Champ. paras.,” p. 74, 
+ Ibid., p. 76. § De Bary, ‘ Brandgilze,” p. 33. 
| De Bary, “‘ Vegl.,” p. 109. 4] De Bary, ‘‘ Brandpilze,” p. 31. 
