158 FRUITS. 



(80) Cubebs. 

 The fruit of Piper Cubeba, Linn. (N.O. Piperacese). 



A transverse section of the fruit exhibits the following 

 structure : 



(1) An outer epidermis, consisting of a single row of brown 

 cells. 



(2) An interrupted outer sclerenchymatous layer, sometimes one 

 sometimes two cells thick ; these cells are irregular in shape 

 and have thick, pitted walls. 



(3) Parenchymatous tissue, composed of polygonal cells, con- 

 taining a few starch grains; large oil-cells are scattered 

 throughout this tissue, which often exhibits a differentiation 

 into an inner and an outer layer (compare black pepper) ; near 

 the middle it is traversed by nbro-vasoular bundles. 



(4) An inner sclerenchymatous layer, consisting of an unin- 

 terrupted single or sometimes double row of sclerenchymatous 

 cells ; these are radially elongated and have very thick, pitted 

 walls ; they are larger than the cells of the outer sclerenchy- 

 matous layer, and exhibit in surface view considerable 

 regularity. 



(5) An inner epidermis, composed of a single row of small 

 cells, with thin, finely-pitted walls. 



(6) The seed-coats, in which the following layers may be dis- 

 tinguished: (a) An outer layer consisting of elongated cells 

 with brown, thickened, wavy walls ; near the hilum the walls of 

 these cells are very sinuous ; (b) a central layer, consisting of 

 large, polygonal cells, with straight, colourless walls; (c) an 

 inner layer of small, brown polygonal cells. 



(7) A perisperm, of which nearly all the kernel consists ; the 

 cells are large, polygonal, thin-walled and packed with small 

 starch grains. This tissue contains large rounded oil-cells. 



The diagnostic characters of powdered cubebs are: 



(a) The outer sclerenchymatous layer. 



(b) The inner sclerenchymatous layer. 



(c) The perisperm packed with small starch grains. 



(d) The blood-red colour produced by concentrated sul- 

 phuric acid. 



(e) The oil cells, many of which are broken. 



