98 BOTANICAL GAZETTE [AUGUST 
1900. SMITH, R. W. The achromatic spindle in the spore mother-cells of 
Osmunda regalis, Bot. GAZ. 30: 361. 
1896. STRASBURGER, E. Karyokinetische Probleme. Jahrb. Wiss, Bot. 
ga2151. 
1897 — Ueber Cytoplasmastructuren, Kern- und Zelltheilung. Jahrb. 
Wiss. Bot. 30:375. 
1g00. Ueber Reduktionstheilung, Spindelbildung, Centrosomen, 
und Cilienbildung im Pflanzenreich. Jena, 1900. 
1897. WEBBER, H. J. Peculiar structures occurring in the pollen tube of 
Zamia. Bor. GAZ. 23: 453 
1899. WEIGAND, K. M. The deechapaieut of the microsporangium and 
microspores in Convallaria and Potamogeton. Bot. GAZ. 28: 328. 
1899. WILLIAMS, C. L. The origin of the karyokinetic spindle in Passzflora 
coerulea. Proc. Cal. Acad. Sci. III. Bot. 1: 189 
' EXPLANATION OF PLATES XV AND XVI. 
The figures were drawn with the Abbé camera, Zeiss apochromatic 
immersion obj. 12™", 1.30 ap., compensating ocular no. 6. 
PLATE XV.— Fics, 1-11. [ris florentina. 
Fig. 1. A pollen mother-cell; cytoplasm in contact with nuclear mem- 
brane ‘al Hikes into a weft of kinoplasmic fibrils, forming a narrow zone 
surrounding nucleu 
IG. 2. Slightly cabitis stage; kinoplasmic weft of considerable but not 
uniform thickness, preparatory to forming primary cones of spindle. 
Fic. 3. Older; outward projections of the weft developed into a distinct 
sharp-pointed cone. Fibrils composing the cone no longer ange to:the 
nuclear wall, but directed outward and convergent at apex of con 
_ Fie. 4. Like fig. 7, but also shows that cones do not pen simul- 
taneously. 
1G. 5. wo cones nearly fully developed; a third beginning. 
Fic. 6. Three primary cones of about the same size. Up to this stage 
nuclear wall is intact, taking no part in formation of kinoplasmic en 
nucleolus also persistent and now vacuolate. 
Fic. 7. Nuclear wall and nucleolus have partly disappeared; fibrils at 
base of cones have grown inward and some have joined chromosomes. 
Fig. 8. A characteristic multipolar figure; the three cones have evidently 
resulted from the union of several primary cones. 
FIG. 9. Somewhat older stage showing further fusicn of cones att 
apices, 
Fig. 10. Cones have united into two groups with their apices pointing “e 
opposite directions, indicating the position of the bipolar spindle. 
11. Mature spindle 
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