THE PI.ANT WORIvD 301 



are found the standard grasses and legumes of America and of Europe. 

 In the extreme southeast corner of the exhibit are some ornamental grasses. 

 To the west of Florida is shown a large number of miscellaneous grasses 

 and forage plants, all of which are of more or less importance to American 

 agriculture. In the portion of the exhibit devoted to standard grasses, 

 particular attention is called to the several varieties of timothy exhibited. 

 These were originated by Dr. A. D. Hopkins, formerly of the West Vir- 

 ginia Agricultural Experiment Station, now of the Department of Agri- 

 culture, and show what possibilities exist in the way of securing new 

 varieties of the standard crops. 



CROP ROTATION. 



At the request of the Bureau of Forestry of the Department of Agri- 

 culture, a system of crop rotation was devised in conjunction with its 

 outdoor exhibit adjoining that of the Bureau of Plant Industry. As the 

 forestry exhibit is intended to illustrate the use of trees as windbreaks 

 upon a prairie farm, a system of crop rotation has been worked out for a 

 general stock and grain farm in the prairie sections of the Middle West. 

 On account of the fact that alfalfa is one of the crops adapted to that 

 section and is also a crop that remains productive for many years, the 

 rotation has been planned with a view to leaving one of the fields in 

 alfalfa for as long a time as may be desired, devoting the remaining five 

 fields to the following rotation: Wheat, meadow, pasture, corn, oats. 

 The alfalfa may be transferred from one field to another, following the 

 oats. The transfer should, therefore, be made during the year the oat 

 crop occupies the field to which it is desired to transfer the alfalfa. 



Some advantages of the particular rotation outlined are : The meadow 

 grasses may either be sown with the wheat or put down in the summer 

 after the wheat crop is removed ; the meadow may be used for pasture 

 the second year and affords a good place for manure for the corn crop 

 following. In such a system most of the manure would naturally be put 

 upon the grass land before plowing for corn. 



CORRESPONDENCE. 



Editor The Plant World : Naturally more or less matter in every 

 periodical is valueless to each individual subscriber. There should be in 

 each issue something for the boxes, the "bald headed row," and the 

 "gallery gods." It strikes me that The Plant World is filling the 

 bill in this way as well as any botanical publication. Even if it contained 

 no other than the famous Guam articles, it has furnished instruction and 

 delight to readers of almost every class. 



Truly the editor should listen to the " howls " of the subscribers, but 

 he should not cut out the politics and tactics of the Wild Flower Preser- 

 vation Society, for instance, just because a few subscribers find them 

 dreary. * * * 



The greatest fault of The Plant World is that it comes but once a 

 month and contains only twenty-five pages. Eet us have collection 

 experiences, peculiar habits, and semi-technical explanations of interest- 

 ing facts and it will grow gloriously. O. W. Barrett. 

 Mayagiiez, Porto Rico. 



