Plant Study . 15 



are very likely to be injured for germinating purposes. When 

 seeds are dry they can withstand considerable cold. The rea- 

 son for protecting seeds from pests is obvious. 



Quality of seeds to purchase. The farmer when purchasing 

 seeds should see that they are plump and well filled. Shrunken 

 seeds seldom produce healthy plants. The purity of the seeds 

 must be considered, also, by purity being meant the presence 

 or absence of weed seeds. Small seeds like clover and alfalfa 

 often contain weed seeds and if planted many weeds will grow 

 in the field. The difference between the cost of good and of 

 poor seeds is very small. 



10. Propagation of field, vegetable, and greenhouse crops 

 by division. Some plants propagate themselves naturally 

 by division ; others are propagated by artificial means. The 

 extent to which propagation by division is used will be learned 

 from the succeeding paragraphs. 



Division of the crown. Propagation by dividing the crown 

 of the plant is practicable with rhubarb, dahlia, globe artichoke, 

 and a few others. It consists in cutting the crown into two 

 or more parts while the plant is dormant and planting these 

 parts to form new individuals. In the case of rhubarb, which 

 may be taken as an example of a plant propagated by this 

 method, a piece of root containing a strong eye, or bud, will 

 produce a good specimen in one season, but the stalks will not 

 be ready for cutting until the second year. The roots can be 

 cut into as many pieces as there are good eyes, but most grow- 

 ers find it a better practice to allow two eyes to remain on each 

 piece. 



Specialized buds. Some species are provided with spe- 

 cialized buds that can be planted to propagate new individuals. 

 These specialized buds are known as bulbs, bulblets, corms, 

 and tubers. A bulb is a very short stem that contains a ter- 

 minal bud surrounded by scales, the enlargement of the onion 

 plant being an example. Bulblets are small bulbs that grow in 

 the axils of the leaves of certain plants, as in the tiger lily, or at 



