240 BOTANICAL GAZETTE [ OCTOBER 
The cells of Pinus are moderately large and the karyokinetic 
figures distinct, but usually there is a considerable amount of 
oil present which is stained readily by most of the stains used, 
and thus interferes with the observation of the finer details of 
structure, especially with the centrospheres. 
In the resting nucleus (fg. z) the chromatin is arranged in a 
granular network with rather large meshes. Several nucleoli of 
various sizes are usually present, surrounded by hyaline areas. 
In normal cells of this stage no centrospheres were observed, 
although a diligent search was made for them. This might be 
taken to indicate that centrospheres are entirely absent in the 
resting stage, which would be contrary to the condition Schaffner? 
reported for Allium Cepa, where centrospheres are said to 
occur in resting cells as well as in the stages of division. 
However, the cytoplasm usually contained many oil drops 
and other granular contents so that if centrospheres were 
present they could not be distinguished very easily. In 
the outer layer, near the epidermis, elongated cells are some-. 
times found (jig. 3) which contain greatly elongated nuclei 
having spindle-like projections with bodies resembling cen- 
trosomes at the outer ends. Sometimes these bodies have 
radiations around them which make them strongly resemble the . 
poles of atrue spindle. Although the nucleus is in the resting 
Stage the bodies might represent the poles of spindles which 
formed earlier than usual. However, the cells in this region 
seldom divide, and the phenomenon may be only an accompani- 
ment of the elongation of the nucleus, the centrosome-like bodies 
representing accumulations of cytoplasm. 
In the stele the elongated cells (fig. ¢) contain very large 
nuclei having numerous nucleoli. In such cases the nucleoli 
are usually very large and filled with vacuoles. The nucleoli 
stain very dimly, so that the chromatin network is hardly visible 
even in well stained sections, while the nucleoli take a deep red 
stain with safranin, and are arranged in a line within the nucleus 
at somewhat regular intervals. 2 
?Bor. Gaz. 19: 445-459. 1894. 
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