236 PLANT ORGANS OR PARTS OF PLANTS. 



prominence of the vein is due. Stomata are numerous, 

 particularly on the lower surface. Many cells of the 

 epidermis contain groups of crystals, said to be hesperi- 

 din. 



The Fruit. — The epidermis of the mericarp is com- 

 posed of irregularly thickened and finely striated cells, 

 with occasional stomata. Within this layer lies the meso- 

 phyll of thin- walled, compressed polygonal cells, which 

 in the unripe fruit contain starch and chlorophyll. In 

 each rib is a fibro-vascular bundle. These consist of a 

 central bast bundle, with, on either side, a smaller sieve 

 bundle, and on the inner side of the whole a group of 

 vessels. The bast fibres are of the usual type. The ves- 

 sels are mostly spirally marked. Near each bundle, on 

 the outer side, lies a small resin duct. Surrounding the 

 seed are two very characteristic cell-layers, the outer of 

 large tangentially elongated cells with dark-colored walls, 

 much thickened on the inner and lateral faces. The 

 layer within, the eridocarp, is formed of cubical or slightly 

 radially elongated cells whose brown walls are somewhat 

 thickened on the inner and outer faces, while remaining 

 quite thin on the sides. It is this endocarp which con- 

 tains the active principle of the drug. Within the en- 

 docarp is a seed-coat of small, thick- walled cells surround- 

 ing the polygonal cells of the albumen which are filled 

 with aleurone grains and fat. The aleurone grains are 

 mostly 5 to 6 microns in breadth. They often contain 

 one or more round or irregularly swollen masses or single 

 or agglomerated crystals of calcium oxalate. (Tschirch 

 and Oesterle.) 



The absence of oil tubes serves to distinguish this fruit 

 from all others of the Umhelliferce. 



Chemistry. — The fruit contains four alkaloids, — conine, 

 methyl conine, conhydrine, and pseudoconine, — a little 

 volatile oil of a conium-like odor, fat, and 6 per cent, of 

 ash. 



