GRASS TYPE OF SEEDS 61 



the seeds themselves are valuable on account of the oil, protein, 

 starch, or alkaloid-like substances which they contain. From the 

 endosperm and embryo of the Flax seed, linseed oil, the chief sol- 

 vent for paints, is obtained. After the oil is pressed out of the 

 flax seed, there remains the cake, which has considerable value as 

 a feed for stock. The Castor Bean yields castor-oil which is 

 much used as a medicine and sometimes as a lubricant and illu- 

 minant. Buckwheat, which contains much starch and some fat 

 and protein, is much used for food when ground into flour. Often, 

 as in case of the Tomato, Potato, Beet, and Tobacco, the value 

 of the plants depends upon the fruit, tubers, roots, or leaves, and 

 not upon the seed, which in these cases has no value except for 

 growing new plants. Of the weed seeds of this type, some com- 

 monly occur as impurities among the seeds of Clover, Alfalfa, 

 Flax, and the small grains and, when present in considerable quan- 

 tities, they either lower the price or prevent the sale of these agri- 

 cultural seeds, thus bringing loss to the farmer. In case of Cow 

 Cockle and Corn Cockle, the seeds, which are frequently found 

 among the small grains, are poisonous and when ground with 

 Wheat make the flour unwholesome and when fed with grain to 

 stock often cause injury. Other weed seeds of this type, as those 

 of Dodder, Morning Glories, Black Bindweed, Sheep Sorrel, and 

 others are objectionable because the plants themselves hinder 

 the cultivation and growth of useful plants. Sometimes, as in 

 case of the Black Nightshade and Jimson Weed, the plants are 

 poisonous. 



Grass Type of Seeds. — As the name suggests, these are the 

 seeds of the Grass family, the family to which Corn, Wheat, Oats, 

 Rye, Barley, and Rice belong and hence the family most depended 

 upon for food. Many of the Grass seeds, as in case of Timothy, 

 Red Top, Blue Grass, etc., though not used for food, are valuable 

 because the plants themselves are useful for pasture and hay. 

 Some of the Grasses, however, are regarded as weeds and their 

 seeds are often troublesome impurities among agricultural seeds. 



As previously noted, in structure the seeds of -the Grass type 

 are not true seeds. Besides a seed, they contain the ovary wall, 

 called the pericarp, which remains about the seed as a closely 

 fitting jacket. They are one-seeded ovaries and hence struc- 

 turally they are fruits rather than seeds. Although popularl}^ 

 known as a seed, this fruit-like structure of the Grasses is scien- 



