98 PLANT LIFE OK THE FARM. 



struggle is less than that of the grasses and of the legu- 

 minous plants. The proportion in which they occur on 

 the several manured plots is always less than that of the 

 grasses, and they never really attain any very great de- 

 gree of prominence, except in cases where from seasonal 

 or manurial causes the grasses are prevented from attain- 

 ing their full development. Those species which, like 

 Rumex Acetosa, have a powerful underground develop- 

 ment, and abundant capacity for collecting and storing 

 water, etc., of course have an advantage especially when 

 it so happens that they can avail themselves of unoc- 

 cupied territory, which they seize and hold with great 

 success against all comers, and also in cases where the 

 density of the soil is such as to offer an obstacle to the 

 penetration of fibrous roots. But, on the whole, the 

 dense fibrous net-work of roots made by the grasses, 

 which enables them to avail themselves of well nigh 

 every particle of soil within their reach, is a more valua- 

 ble possession than is the more robust underground root- 

 stock possessed by several of the miscellaneous plants. 

 Most of the species occur in too insignificant amounts to 

 be considered as anything more than accidental tenants, 

 and while in others their preponderance depends on the 

 relative inferiority of the growth of grasses, there are 

 also indications that some of them are favorably affected 

 by certain manures, and others by fertilizing agents of 

 different character. But on the whole, these indications 

 observed on plants growing in association are by no means 

 so marked as in the cases of the grasses and the Legu- 

 minosse. 



Growth of Pasture Plants when unaffected by manure 

 of any kind. The changes from year to year in the vege- 

 tation of a plot which has been unmanured for many 

 years must obviously be mainly due to seasonal influ- 

 ences, and progressive exhaustion of the soil, while those 



