86 PKACTICAL BOTANY 



sections so as to traverse the pith. Stain with hsematoxylin, 

 wash with alcohol, transfer to oil of cloves, and mount in 

 Canada balsam (p. 52). In sections so prepared, if the staining 

 be not too deep, cells may be found whose nuclei may show 

 various stages of formation of the nuclear spindle, the cell-plate, 

 and new cell-wall. The process in its essential points is similar 

 to that above described, and it may be traced by a comparison of 

 the various stages which may be found in the cells of the pith or 

 cortex : pith which is of such age that the cells are not longer 

 than they are broad will give the best results, and care must be 

 taken that the sections be not over stained. Longitudinal sections 

 of the scape of the Hyacinth, not more than three or four inches 

 in length, will also give good results. 



Node. 



VI. Cut moderately thick longitudinal sections 

 through a young node of the Sunflower, so as to 

 include the median plane of the leaf, or of both leaves 

 if they be opposite, as they often are in the lower part 

 of the plant. Treat with potash and glycerine, and 

 warm for a few minutes ; or better, treat with " eau de 

 javelle," as directed on p. 50 : mount in glycerine, and 

 examine with a low power. 



The course of the vascular bundles, which appear 

 dark, is easily followed through the more transparent 

 parenchyma. Note 



1. The continuity of tissues of the stem and petiole; 

 there is no definite boundary between these two parts. 



2. That the bundles from the petiole pass into the 

 stem, and, curving at first inwards, they soon assume a 

 longitudinal course. 



3. That no bundle of the upper internode lies in the 

 same vertical plane as the bundle which enters from 



