3o6 
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DESCRIPTION OF PLATE XV 
The photomicrograph was made with i}^ inch Professional Bausch and Lomb objec- 
tive 24° and ocular 7.5 X with the plate at a distance of 42 centimeters from the slide. 
The drawings were made after tracing the outline with a camera lucida. A Zeiss homo- 
geneous immersion 2-mm. lens with aperture 1.30 was used with an 8 X ocular at a tube 
length of 145 mm. 
Fig. I. Photomicrograph of median longitudinal section of an anther of Nelumbo 
lutea^ showing two pollen chambers with little more than a single row of pollen mother cells 
disposed freely within each pollen chamber. 
Fig. 2. Pollen mother cell in a very late anaphase stage showing the lateral view of 
one spindle and a polar view of the other. Eight chromosomes may be counted. No evi- 
dence of a cell plate across the equator of the spindle is apparent. 
Fig. 3. A tetranucleate stage in pollen formation. The nuclei have already enlarged 
somewhat. A cell plate, if present, should be well formed at this stage, but there is no 
indication of such a structure. 
Fig. 4. A late stage of quadripartition by . furrowing. The cytoplasm has become 
progressively more and more fibrillar, and the nuclei are larger. Note the relative thinness 
of the furrow and its uniform width. The unequal thickening of the mother-cell wall is 
well shown in this figure. 
