THE PRINCIPAL TISSUES. 



73 



(<f) The hard tissues of nuts and of stone fruits furnisli excellent ex. 

 amples of short and very thick-walled sclerenchyma-cells. In the 

 hickory nut {Carya alba) the cells (Figs. 58 and 59) are not more than 



FiQ. 58. 



Fig. 59. 



Fig. 58. — Sclerenchyma-cells of the sliell (enclocarp) of the hickory-nut (Carya 

 <rf6a), taken parallel to the t-urface of the nut. x 400. 



Fig. 59. — Sclerenchyma-cells r)f the ehell fendocarp) of the hickory-nut {Carya 

 alba)^ taken at right-angles to the BUrt'ace of tne nut. X 400. 



two or three times as lonor as broad, and the thickening is so great as 

 almost entirely to obliterate their cavities ; the thickened walls are 



c 6 



Fig. 60. 



Fio. 61. 



Fig. 60.— Sclerenchyma-cells of the seed-coat of Echinocystis lobata, from a section 

 at right angles to the surface of the seed ; a, a cell cut directly through Its centre, 

 showing the whole of the cavity— the three dark ppots are probably oil ; 5, a cell 

 cat through at one side of the middle ; c, a cell whose cavity was not cut Into in 

 making the section. X 850. From a drawing by J. 0. Arthur. 



Fir"' "• ' ,. ... , . .„ 



paral 



g. 61. — Sclerenchyma-cells of the seed-coat of Echinncyslis Idbata, from a section 

 iTlel to the surface of the seed. X 850. From a drawmg by J. C. Arthur. 



pierced by many deep pits. Tlie cells are arranged with their longer 

 axes perpendicular to. the surface of the nut, and are very closely 

 packed togetlier. 



