92 PHENOMENA OF PLANT-LIFE. 



FIG. 7 is a transverse section of the petiole of a leaf. 



A, internal cavity. 



B, fibro-vascular bundles. 



C, vertical dark green striae between the bundles, consisting of 



parenchyma containing chlorophyl. 

 FiG. 8 exhibits a transverse section of the branch of a tendril. 



A, the inner sensitive surface of loose cellular tissue, which 



contracts and expands as the branch coils and uncoils. 



B, bast fibre or elongated fusiform cells. 



C, fibro-vascular bundles 



FIG. 9 represents the androaciuni of the staminate flower with connected 

 sinuous anther cells, which are open and discharging pollen 

 grains. 



FIG. 10 is a pollen grain oi spherical form and covered with projecting 

 spines. 



A is the opening in the outer membrane through which the 

 tube develops after its lodgment on the stigmatic surface 

 of the pistil. 

 FIG. 11 shows the gynsecium of the pistillate flower. 



A, ovary. 



B, style. 



C, stigma. 



FIG. 12 is a vertical section of the pistil. 



A, the receptacle, or stem. 



B, the wall of the ovary, the fibres of which are arranged in 



three distinct layers. The outer and inner ones have the 

 fibres extending from the base to the apex of the ovary, 

 or young squash, while the central one consists of fibres 

 running around the ovary at right angles to the other 

 two. 



C, ovules imbedded in loose cellular tissue. 



D, canal of the style through which the pollen tubes find their 



way to the ovules. 

 FIG. 13 represents a transverse section of the ovary, showing the three 



layers of the tissues of the wall and the cells of the ovaiy with 



ovules attached to the inner edges of the carpellary leaves. 

 FIG 14 exhibits the propagating pit with the squash in harness, and the 



squash root of a second vine attached to a mercurial gauge to 



show the pressure of the sap. 



A, the box in which the squash was placed. 



B, the lever to support the weights. 



C, the root from which the principal vine grew. 



D, the root of the vine which was cut off when eight weeks 



old, and connected with a gauge. 



E, mercurial gauge. 



F, scale to indicate the variations in the position of the lever. 

 FIG. 15 gives a view of the apex and lower side of the squash, after it 



had completed its growth, and been taken from the box in 

 which it had been confined. 



