258 



Methods in Plant Histology 



through the nucellus toward the archegonia, and consequently, in 

 some of the material, it is better to retain enough of the tissues of the 

 ovule to keep the nucellus in place. In later stages, after fertilization 



FIG. 90. Pinus Laricio: photomicrograph showing the formation of the ventral 

 canal cell; usually, this cell is not so large in proportion to the egg; fixed in Flemming's 

 weaker solution and stained in safranin, gentian-violet, orange; the preparation was made 

 in 1897, the photomicrograph in 1915; Cramer contrast plate; 4mm. objective; ocular 

 X4; Abbe condenser; yellowish-green filter and also a strong filter used in outdoor 

 photography; camera bellows, 75 cm.; arc light; exposure, 7 minutes. X587. 



has taken place, the developing testa should be removed with great 

 care, for a very slight pressure is sufficient to injure the delicate parts 

 within. 



