24 



SCIENCE OF GARDENING. 



plant, the seed leaves, having falfilled the office assigned 

 to them by nature, soon wither and decay. 



The seed leaves, are, therefore, of such vital imj^ortance 

 to plants, at an early stage of their existence, that if they 

 are destroyed at this j^eriod of their gro\vth, either by 

 insects, such as the turnip-fly, snails, slugs, or grubs, or by 

 birds, frost, or other casualties, they seldom recover, and 

 the whole crop generally perishes. This is not unfre- 

 quently the case with young turnips, radishes, and cab- 

 bages : and the only alternative, where it is permitted to 

 occur, is to dig the ground slightly over, and sow it afresh. 

 The greatest care, however, should be exercised to prevent 

 such an accident, as it will frequently throw the crojDtoo 

 late to be of any real use. 



Propagation by seeds, then, being the most natural and 

 easy means of multiplying plants, should ordinarily be 

 preferred. But some plants, as the foreign geraniums, 

 and most double flowers, do not ripen seed ; in others, 

 as the rose, the seeds are generally two years in the ground 

 before they vegetate, and do not produce flowers for 

 several years after; and in other cases, each seed will pro- 

 duce a plant essentially different from the parent species. 

 This latter circumstance has been taken advantage of by 

 gardeners and florists, and hence are produced the almost 

 innumerable beautiful varieties of the dahlia, chrysanthe- 

 mum, heart's-ease, tulip, ranunculus, and many otliers 



