y'Ecidiospores. 



tion, by Mr. W. G. Smith, was taken from the living plant, 

 and is therefore reliable, although my own impression was 

 that the elongation of the pseudoperidia was not quite so 

 pronounced. In some species the cells of the peridia 

 naturally adhere more firmly, as in ^c. ornainentale, Peri- 

 dermmin, Rcestelia. In ^cidium pint the peridium opens 

 at the apex, but the margin shows very little tendency to 

 become recurved. In R. cancellata the peridia do not open 

 at the apex. This remains entire for a long time, and 

 surmounts the peridium as a conical cap. The peridial 

 cell-series, however, below this separate from one another 

 laterally, so that the spores escape through a number of 

 longitudinal fissures — a sort of lattice-work. 



The membrane of the aecidiospore is not of uniform 

 strength, inasmuch as at certain points, when the spore 

 germinates, there are pushed through it prolongations or 

 outgrowths of the endospore. These potential openings 

 (germ-pores) are exceedingly difficult to observe in the 

 mature spore. When, however, the spore begins to ger- 

 minate, they become obvious. De Bary * gives the 

 number of germ-pores in. /Ec. tragopogonis as three, and 

 those of ^c. asperifolii f as four. From my own observa- 

 tions, I should say the aecidiospores of Puccinia graviinis 

 and poarinn have six germ-pores. When these spores 

 begin to germinate they become somewhat quadrangular, 

 with a germ-pore at each angle ; but in addition to these 

 a central opening or thin place appears in the centre of 

 that side of the spore which is uppermost, and a.s, of 

 course, both the upper and under sides of a spore cannot 

 be seen in the same preparation at the same time, it 



* De Bary, "Champ, parasit," Ann. des Sci. Nat., 4« ser. tome x.x., 



Reprint, p. 76, t. ii. fig. 7. 



t De Bary, " Neue Untersuchungen iiber Uredinccn," vol. ii. p. 209, 

 Berlin : 1866. 



