794 



BOTANY AND PHARMACOGNOSY. 



a fixed oil and aleurone grains, thick-walled, finely porous and 

 giving a blue or violet color. with potassium dichromate and 

 sulphuric acid. Small, nearly spherical starch grains occur in 

 the tissues of adhering fruit pulp. 



253. ALMOND. — Both bitter almonds and sweet almonds 

 lave characteristic, rectangular, somewhat rounded stone cells in 

 the outer epidermal layer of the seed-coat. These stone cells are 

 from 70 to 17s /i long and from 65 to 100 fi wide; the walls are 

 from 10 to 15 ;u, thick and have numerous simple pores. The seed- 



ep 



■ Fig. 3ig. Almond meal: a, stone cells of the outer epidermis: K, brown hypodermal 

 cells; sp, spiral tracheae of the seed-coat; ep, cells of inner epidermis with brown contents; 

 E, cells of the endosperm containing numerous small aleurone grains; Ca, epidermal cells 

 of cotyledons; C, parenchyma of the cotyledons containing aleurone grains and oil. — After 

 JMoeller. 



coat also contains tracheae with spiral thickenings, associated with 

 which are cells containing rosette-shaped or prismatic crystals of 

 calcium oxalate that are about 7 /«■ in diameter. The endosperm 

 consists of a single layer of nearly cubical cells about 15 /* in 

 diameter. The cells of the embryo contairt numerous aleurone 

 grains, which are from 5 to 15 //, in diameter and consist of crys- 

 talloids, globoids and calcium oxalate (Figs. 187; 188; 302, D; 



319)- 



Substitutes. — The seeds 'of other plants of the Rosaceae are 

 sometimes substituted for Almond seeds. These usually have a 

 bitter and more or less disagreeable taste; the outer epidermal 

 cells in apricot and plum being elongated tangentially, while 

 those of peach are somewhat narrower arid more or less conical. 



