50 BOTANICAL GAZETTE [JULY 
Fic. 2. Peculiar aster at upper pole; the papilla indicates that it is pull- 
ing upon the nuclear membrane. 
Fig. 3. The cap is very conspicuous and the nuclear membrane is still 
intact. 
Fic. 4. A cap just beginning to break up into fibers. A transverse section 
at this stage shows a ring. 
Fig. 5. Transverse section of fully formed spindle. 
Fic. 6. Mitosis in late prophase; the spindle is evidently made up of 
two half spindles: radiations conspicuous; definitely formed centrospheres 
are lacking. 
Fic. 7. Metaphase of third mitosis; no radiations or centrospheres are 
present. Figures of first mitosis are the same at this stage. 
Fig. 8. Irregular mitosis (third mitosis) in an unusually large spore, sug- 
gesting how nuclei with an irregular number of chromosomes might be 
ed 
1G. 9. Mitosis near apical cell; caps prominent and radiations reaching 
to the Hautschicht ; at the upper pole is a granule resembling a centrosome. 
Fic. 10. Anaphase in mitosis near the apical cell; no asters or centro- 
spheres are present. 
PLATE X11. 
(Figs. 17-17, second mitosis; z8—20, third mitosis in germinating spore.) 
Fic. 11. Very early prophase. 
Fic. 12. Centrosphere and radiations. 
Fic. 13. Very prominent centrosphere and radiations. The centripetal 
ends of the radiations have a pseudopodium-like aspect and suggest that the 
radiations are lines of streaming material. 
Fic. 14. Centrosphere in which the cut end of a fiber resembles a centro- 
some. There is no centrosphere or aster at the other pole. 
Fic. 15. Irregular, elongated centrosphere with prominent aster; 10 
centrosphere or aster at the other pole 
Fic. 16. Tripolar spindle, the third pole not shown. The cut end of a 
fiber resembles a centrosome. The pull upon the nucleus is evident; upper 
aster at some distance from the nucleus. 
Fic. 17. The two centrospheres are practically alike, but the upper one is 
shown in median section, while the lower one appears in surface view, the 
fibers having the appearance of granules within a centrosphere. 
Fic. 18. The more usual appearance of an early prophase at the third 
mitosis ; prominent caps, but no centrosphere or very definite aster. 
Fic. 19. An exceptionally prominent centrosphere and aster at the third 
mitosis ; no centrosphere or aster at the other pole. 
FiG. 20. Transverse section of mitotic figure at the third mitosis; just 
before the splitting of the chromosomes, showing nine chromosomes. 
