BOT.— Vol. I.] IVILLIAMS—PASSIFLORA CCERULEA. 1 91 



When the sections were sufficiently decolorized the clove 

 oil was removed by placing the slide in xylene for a 

 few moments. The sections were finally mounted in Can- 

 ada balsam. 



In the young pollen-mother-cell, when the chromatin is 

 still in the spireme stage (fig. i), the cytoplasm is composed 

 of two distinct elements. One is fibrous and forms a net- 

 work throughout the cell from the nuclear wall to the cell- 

 wall. The other is granular and is uniformly distributed 

 within and upon the meshes of the network. The threads 

 of the reticulum are knotted and sinuous and take the 

 violet stain. The granular part of the cytoplasm usually 

 stains yellow or yellowish brown. About the time when the 

 chromatin thread breaks up a change takes place in the 

 cytoplasm. The meshes of the reticulum immediately sur- 

 rounding the nucleus are drawn out parallel to the nuclear 

 wall and form a sort of weft about it (fig. 2). This con- 

 dition of the cytoplasm is of short duration. Soon the 

 meshes of the cytoplasmic reticulum assume a new arrange- 

 ment. They become drawn out at right angles to the 

 nuclear wall and appear as if radiating from the nucleus 

 (%• 3)- -^ little later, irregular, deeply staining strands 

 appear in the cytoplasm (fig. 4). For the most part, they 

 are radially arranged and extend toward the cell-wall; some 

 of them reach it. In one or two instances similar stages 

 show groups of fibers outside the nuclear wall. These 

 groups are conical with their bases directed toward the 

 nucleus; they resemble the cones of Equisetum (Osterhout 

 1897, fig. 4). Their subsequent fate could not be deter- 

 mined; no trace of them was seen in later stages. 



The radial arrangement of the cytoplasmic reticulum 

 spoken of above disappears after a short time, and the fibers 

 of the cytoplasm again form an irregular network as in 

 figs. I and 2. The meshes show no tendency to be drawn 

 out in any one direction, although a few deeply staining 

 strands radiate from the nucleus (figs. 6, 7 and 9). Changes 

 in the nuclear wall resulting in its transformation into a 

 meshwork now begin. The first evidences of such change 



