320 Explanation of Plates. 



PLATE XL. 



(All Figures X 500.) 

 NORMAL AND ABNORMAL SPORES OF PUCCINIA AND UROMYCES. 



PUCCINIA DICHONDRAE. 



Fig. 



299. The teleutospores exhibit a great variety of shape and size, and range from one 



to four celled forms. In the two-celled forms the septum may either be 

 transverse or longitudinal, and in the three-celled forms the septa may 

 either be transverse or oblique, and the upper or lower cell may be divided 

 longitudinally. The four-celled forms may, in addition, become somewhat 

 spherical, and be divided longitudinally and obliquely, so as to resemble 

 a S^haero-phragmium. The variation even in the same sorus is sometimes 

 greater than it is between some different species. 



PUCCINIA LUDWIGII. 



300. Teleutospores may be divided generally as in the above, although the four- 



celled forms are not quite so frequent. 



PUCCINIA GRAMINIS. 



301. Teleutospores are also one to four celled, but the septa are generally transverse, 



while the upper cell may occasionally be longitudinally divided. 



PUCCINIA TRITICINA. 



302. The teleutospores do not show such a wide variation as in P. graminis, but they 



may be from one to three celled, and the upper cell may be longitudinally 

 divided. 



UROMYCES ORCHIDEARUM. 



303. This species shows very well the transition from the unicellular (Uromyces) to 



the bicellular (Puccinia) teleutospores. Some of the two-celled spores are 

 equally divided by the transverse septum and constricted, so that they depart 

 entirely from the Uromyces type. 



