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METHODS IN PLANT HISTOLOGY 
Fig. 62.— Puccinia, graminis: A, uredospores on oats, showing binucleate mycelium and 
binucleate uredospores with binucleate stalk cells; c, chloroplasts, and n, nuclei of host cells; 
B, C, and D, stages in the development of the teleutospore; the two nuclei of the binucleate cells 
in C fuse to form the uninucleate cells of D. X780. 
Fig. 63.— Gymnosporangium: A, beginning of germination of teleutospore; B, later stages, 
the lower basidium showing the nucleus in the synapsis stage of the heterotypic mitosis, and the 
upper basidium showing the four-cell stage following the homotypic mitosis; C, the two figures of 
the homotypic mitosis; D, E, F, and G, later stages showing the formation of basidiospores, many 
of the basidiospores being binucleate— g, gelatinous stalk; b, basidiospore; s, sterigma. Fixed 
in 10 per cent formalin and stained in iron-alum haematoxylin. X800. 
