Nuclear Divisions in the Rusts. 
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membrane appears to be still intact, and the centres and the central spindle are evidently on its 
upper surface. 
Fig. 3. The central spindle now reaches to the poles of the figure. The lower pole is obviously 
double. The chromatin and nuclear sap lie mainly in the swollen lower half of the mitotic figure, 
while the upper part, in the forming spermatium, appears to be made up almost entirely of a fibrous 
material, x 2250. 
Fig. 4. Early anaphase. The densely fibrous central spindle is at one side of the axis of the 
figure. The chromatin is being drawn to the poles somewhat irregularly. The lower pole shows 
some astral radiations. 
Fig. 5. Poorly differentiated late anaphase, from the spermogonium of Uromyces Lilii , showing 
central spindle, mantle fibres, budding spermatium, &c. x 2250. 
Fig. 6. Late anaphase, from Triphragmium , showing at both poles the double centres and 
mantle fibres. The two fibres which extend between the daughter-nuclei are probably a remnant of 
the central spindle. 
Fig. 6 a. A double centre, more highly magnified, showing four chromatic strands attached to 
each half, thus making eight chromosomes to the daughter-nucleus, x 2250. 
Fig, 7. A spermatium, showing its comparatively large nucleus, with a nucleole and centrosome. 
x 2250. 
Fig. 8. A highly magnified resting (?) nucleus from a multinucleated sporophytic cell of 
Puccinia Cirsii-lanceolati , showing the polarized condition, x 3375 - 
Fig. 9. Poorly defined equatorial-plate stage of division, from the spermogonium of Uromyces 
Scirpi. x 2250. 
Fig. 10. Telophase of the mitosis in the gametophytic hypha which cuts off the so-called 
‘ sterile cell ’. The centre in the upper nucleus is distinctly double, and four chromosomes are 
attached to each half. The lower nucleus is seen in obliquely polar view, so that here also about 
eight chromosomes may be counted, radiating from the centrosome. 
Fig. 10 a. Anaphase of a similar nuclear division. 
Fig. 11. Telophase of a mitosis in a gametophytic hypha at the base of the aecidium-cup of 
Uromyces Scirpi . The uninucleated cell which will be cut off at the tip will form a ‘ pseudo- 
parenchyma ’ cell. 
Fig. 12. Prophases of a conjugate division in a fusion cell. The nucleole is apparently about 
to be cast out from the left nucleus. Each nucleus shows (probably on its surface) a dumbbell- 
shaped, dividing centrosome. The strand connecting the two centres doubtless represents an early 
stage of the central spindle. 
Fig. 13. Prophases of conjugate division showing the two nucleoles which have been cast out 
into the cytoplasm ; the two central spindles, the poles of which are each terminated by a disk- 
shaped centrosome ; and the mass of chromatin attached to each spindle. 
Fig. 14. A later stage in which the two spindles lie almost at right angles to each other. The 
nuclear figure at the left is well oriented to show the dense, curving, central spindle, terminated by 
broad centrosomes, and a few mantle fibres, which reach out from the central spindle, apparently to 
pull the chromatin finally to the poles. 
Fig. 15. The double base suggests that two cells have here fused to form the budding ‘basal 
cell’, although no partially absorbed walls remain to confirm the suspicion. The stage in conjugate 
division here represented is somewhat similar to that shown in Fig. 14. The central spindles in this 
instance are, however, unlike the latter case, placed parallel to each other. 
Fig. 16. Early anaphase stage of conjugate division in a young peridial cell from the aecidium- 
cup of Uromyces Scirpi. The two nucleoles lie near the equator of the central spindles, a position 
very commonly assumed in conjugate division. The chromatin in this instance shows the usual 
poor differentiation which seems to be characteristic for vegetative divisions, x 2250. 
Fig. 17. Late anaphase, showing broad-poled spindles, mantle fibres, asters, and vacuolated 
nucleoles. 
Fig. 18. Still later stage of conjugate division. The upper right-hand nucleus has a very 
conspicuous double centrosome. 
Fig. 19. Telophase of conjugate division. About eight chromosomes may be counted, radiating 
from the centre in each nucleus. The companion of the right nucleus lies in a lower plane. 
Fig. 20. Late stage of conjugate division in a basal cell from the aecidium on Cicuta. Note 
the centres, the remnant of the central spindle, &c. 
