MISCELLANEOUS NUTS. 35 



sumers for the most part among the Orientals of the Pacific coast 

 States. During the past season they have occasionally been found 

 among mixed nuts. 



The canarium tree is a native of the East Indies and Philippine 

 Islands. The nuts are fusiform, somewhat triangular in cross sec- 

 tion. The shell, which is thick and very hard, incloses a white, oily 

 [ernel enveloped by reddish-brown seed coats, which are compara- 

 tively thick and tough. The kernel consists of the cotyledons and 

 other structures of the embryo. It separates readily from the seed 



its; and if the inner surface of the latter be scraped lightly, a 

 small amount of white tissue, which is largely endosperm, can be 

 removed. 



Histology. Preparations of the seed coat viewed from the outer 

 side reveal a superficial layer of cells averaging 50 \L in diameter, but 

 occasionally reaching an extreme length of 100 \L. (PL III, fig. 3.) 

 Their general shape is polygonal, with straight or slightly curved 

 vertical walls of considerable thickness. The horizontal walls are 

 sometimes traversed by slight thickenings, which can often be traced 

 but a short distance from the vertical wall, thus forming a sort of 

 false beading. 



Underneath this epidermis is a thin layer of stellate parenchyma, 

 composed of branched cells united with each other only at the ends 

 of the branches, thus leaving large intercellular spaces. (PI. Ill, 

 fig. 4.) These cells are rich in tannin, as shown by the ferric chlo- 

 rid reaction, and are similar in size to the cells of the overlying 

 epidermal tissue. The inner layer of the seed coat consists of polyg- 

 onal cells about 10 [i in diameter, with the walls strongly marked 

 with tracheidlike thickenings. (PL III, fig. 5.) When viewed in 

 section they are seen to be cup-shaped cells, with openings turned 

 toward the parenchyma tissue of the integument. 



Nearly all of the vascular tissue of the seed coat is included in one 

 or two broad bands, running in general in a longitudinal direction. 

 They are easily recognized, when the inner surface of the seed coat 

 is examined, by their thickness and by their reddish color, which is 

 much darker than that of the spermoderm itself. They are scarcely 

 distinguishable on the outer surface. These vascular areas resemble 

 in structure the oth^er parts of the seed coat, except that the inner 

 layer of cup-shaped cells gives way to a layer of nearly square, thin- 

 walled cells about 15 jj, in diameter. The greater thickness of this 

 part of the seed coat is due largely to the vascular elements, mostly 

 annular and scalariform vessels about 15 p, or less in diameter. The 

 parenchyma tissue, which surrounds the vascular bundles, is quite 

 fully developed. The cells are elongated in the direction of the 

 vascular elements and branch almost entirely at the ends. 



