1892.] NEW-VORK. MICROSCOPICAL SOCIETY. 107 



NOTES ON THE STRUCTURE OF THE FRUIT-STONE 

 OF THE DATE, PHCENIX DACTYLIFERA L. 



BY J. L. ZABRISKIE. 

 (Read June s^/, 1892.) 



The sculpturing of cell walls, resulting from thickening de- 

 posits, always presents an interesting field of microscopic inYes- 

 tigation in vegetable structure. The variety of form exhibited, 

 the beauty of tracery and regularity of deposit, as seen in many 

 spiral and annulated vessels, the surprising adaptations to the 

 necessities of the organization, continually encourage examination. 

 A striking example of this thickening of cell walls is afforded by 

 the endosperm of the fruit-stone of the Date. 



The stone is fusiform with irregularly rounded ends (Plate 37, 

 Fig. i). A thin, firm, uniformly light-brown outer coating 

 covers all the surface, excepting that occupied by the deep 

 longitudinal cleft, extending the entire length of one side of the 

 stone, and filled with a dark-brown, soft, cellular structure. When 

 the stem end of the fruit-stone is uppermost, at the lower end of 

 the cleft will be found a little, hard, grooved, conical prominence, 

 projecting downward and indicating the distal end of the fruit, 

 opposite the stem. On the side directly opposite the cleft, and 

 usually a little above the middle of the stone, may be noticed a 

 small circular depression enclosing a hemispherical prominence 

 and indicating the position of the embryo within (Fig 2). A 

 longitudinal section of the entire stone through the cleft (Fig. 3) 

 shows the position of the embryo, which is seated, entirely free 

 excepting a slight detachment at its inner end, in a little ovoid 

 cavity. A transverse section through the entire stone and 

 through the embryo (Fig. 4) shows the inner lateral enlargements 



Explanation of Plate 37. 



Fig. 1— Fruit-stone of the date, showing longitudinal cleft and conical prominence. 

 Fig. 2— The same, showing the position of the embryo. Fig. 3— Longitudinal section, 

 showing the embryo m its cavity. Fig. 4— Transverse section, showing the same. X 3. 

 Fig. 5— The fruit-stone germinating. (Figs. 1, 2, 3, and 5 all natural size.) Figs. 6 and 

 7— A continuous narrow band of the transverse section of the stone, from the seed 

 coats o through h and c to the soft structure of the cleft at d. X 50. Fig. 8— A por- 

 tion of the transverse section at a. •: 100. Fig. 9— A p:>rtionof the same at 6. X 100. 

 Fig. 10— Two cells of the same at c. x 200. Fig. 11— A portion of the same at d. 

 X 200. Fig. 12— Longitudinal tangential section, showing outer seed coats on the left 

 hand and beginnings of the spindle cells on the right hand. X 75. Fig. 13— Three 

 cells from the same section with abundant capillary canals. X 200. Fig. 14— A por- 

 tion of the middle of the same section. X 200. 



