214 PHARMACEUTICAL BOTANY 



seminated by wind currents. Examples of these are seen in the 

 Milkweed, which has a tuft of hairs at one end of the seed called a 

 Coma, and in the official Strophanthus, which has a long bristle-like 

 appendage attached to one end of the seed and called an awn. The 

 wart-like appendage at the hilum or micropyle, as in Castor Oil 

 Seed, is called the Caruncle. 



The tegmen or inner coat surrounds the nucellus closely and is 

 generally soft and delicate. 



A third integument, or accessory seed covering outside of the testa, 

 is occasionally present and is called the Aril. Example: Euonymus 

 (succulent). 



When such an integument arises from the dilatation of the micro- 

 pyle of the seed, as in the Nutmeg, it is known as an Arillode. 



The Nucellus or Kernel consists of tissue containing albumen, when 

 this substance is present, and the embryo. Albumen is the name 

 given the nutritive matter stored in the seed. The funiculus or seed 

 stalk is usually absent in the official seeds. The scar left by its 

 separation is called the hilum. When the funiculus is continued 

 along the outer seed coat, it is called the raphe. 



MODE OF FORMATION OF DIFFERENT TYPES OF ALBUMEN 



If the egg-cell within the embryo sac segments and grows into the 

 embryo and, stretching, fills up the cavity without food material 

 laid down around it, it happens that the nutritive material lingers in 

 the cells of the nucellus, pressing around the embryo. This is called 

 Peris per mic albumen. Seen in the Polygonacea. 



In by far the greater number of Angiosperms, the endosperm nu- 

 cleus, after double fertilization, divides and redivides, giving rise to 

 numerous nuclei imbedded in the protoplasm of the embryo sac, out- 

 side of the developing embryo. Gathering protoplasm about them- 

 selves and laying down cell walls they form the endosperm tissue 

 outside of the embryo. Into this tissue food is passed constituting 

 the Endospermic albumen. 



In the Maranlacea, Piperacea, etc., nutritive material is passed 

 into the nucellar cells causing them to swell up, while to one side a 

 small patch of endosperm tissue accommodates a moderate amount 



