340 AGRICULTURE FOR BEGINNERS 



Ovipositor : the organ with which an insect deposits its eggs. 



Oxygen : a gas present in the air and necessary to breathing. 



Particle : any very small part of a body. 



Perennial : living through several years. All trees are perennial. 



Petal : a single leaf of the corolla. 



Phosphoric acid : an important plant food occurring in bones and rock 



phosphates. 



Pistil : the part of the blossom that contains the immature seeds. 

 Pollen : the powdery substance borne by the stamen of the flower. 



It is necessary to seed production. 

 Pollination: the act of carrying pollen from stamens to pistils. It is 



usually done by the wind or by insects. 

 Porosity: the state of having small openings or passages between 



the particles of matter. 

 Potash : an important part of plant foods. The chief source of 



potash is kainit, muriate of potash, sulphate of potash, wood 



ashes, and cotton-hull ashes. 



Propagate : to cause plants or animals to increase in number. 

 Protein: the name of a group of substances containing nitrogen. It 



is one of the most important of feeding stuffs. 

 Pruning : trimming or cutting parts that are not needed or that are 



injurious. 



Pulverize : to reduce to a dustlike state. 

 Pupa: an insect in the stage of its life that comes just before the 



adult condition. 

 Purity (of seed) : seeds are pure when they contain only one kind of 



seed and no foreign matter. 



Ration : a fixed daily allowance of food for an animal. 

 Raupenleim : a patented sticky substance used to catch the cankerworm. 

 Resistant : a plant is resistant to disease when it can ward off attacks 



of the disease ; for example, some varieties of the grape are resist- 

 ant to the phylloxera. 

 Rotation (of crops) : a well-arranged succession of different crops on 



the same land. 

 Scion : a shoot, sprout, or branch taken to graft or bud upon another 



plant. 

 Seed bed : the layer of earth in which seeds are sown. 



