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1905] CHRISTMAN—SEXUAL REPRODUCTION IN RUSTS 275 
Fic. 6. Same as jig. 5, slightly more advanced; the nuclei lie nearer the distal 
end than in earlier stages. 
Fic. 7. Simultaneous nuclear division following the fusion. 
Fic. 8. A stage following nuclear division in which the fused mass contains 
four nuclei, two side by side in the distal end and one in each of the bases. 
Fic. 9..The aecidiospore mother-cell formed by a cell wall cutting off the 
upper portion of the protoplast. 
Fic. ro. A figure taken from a thick section showing several aecidiospores, 
intercalary cells, and the two gametes at the base; the remnant of the basal part 
of the dividing wall being evident between the two gametes. 
Caeoma nitens. 
Fic. 11. Hyphae of rust massing beneath the epidermis in very young sorus. 
Fic. 12. Series of large upright cells; @, a nuclear division preceding the 
throwing off of the sterile cell. 
Uromyces Caladit. 
Fic. 13. A pair of gametes fused, showing the nuclei in the upper portion 
the protoplast, the large vacuole in the lower part, and the two less conspicuous 
ases, 
