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GLOSSARY 



Nitrification, the changing of nitrogen into a nitrate. 



Nitrogen, a gas forming four-fifths of the air. Nitrogen 

 is a very necessary food of plants. 



Organic matter, substances produced by the growth of 

 plants and animals. 



Osmose, the movement of fluids through membranes or 

 thin partitions. 



Oxygen, a gas which forms one-fifth of the air. Its pres- 

 ence is necessary to the life of all green plants and all 

 animals. 



Ovary, the part of the pistil that bears the developing 

 seeds. 



Ovule, an immature seed in the ovary. 



Perennial, living through several years. 



Phosphoric acid, an important plant food found in phos- 

 phates. 



Pistil, the part of the flower which produces seeds. 



Propagate, to increase in number. 



Pollen, the powdery substance produced by stamens. 



Pollination, the transfer of pollen from stamens to pistils. 



Potash, an important plant food. 



Pruning, removing parts of a plant for the good of what 

 remains. 



Retentive, holding, retaining, said of soil which holds 

 water. 



Reverted, said of phosphoric acid in the process of be- 

 coming insoluble. 



Rotation of crops, a change of crops in regular order. 



Sap, the juice or liquid contents of plants. 



Seed bed, the earth in which seeds are sown. 



Seedling, a young plant just from the seed. Also a plant 

 raised from a seed in distinction from one produced from 

 a graft or a cutting. 



Sepal, one of the parts of the calyx. 



Slip, a cutting placed in water or moist soil or other sub- 

 stance to produce roots and form a new plant. 



Soil, that part of the earth's crust into which plants send 

 their roots for food and water. 



