262 Proceedings of Indiana Academy of Science 



to certain soils. This fact has been familiar for many years. The fur- 

 ther mention of the use of this substance by English farmers to the 

 extent of "two to three hundredweight per acre" shows its value in 

 the soils concerned. Storer'"' and others have made valuable contribu- 

 tions on this point. 



The observations of this study were carried on for two summers on 

 the area here in question. During the first summer the introduction 

 of the forms that appeared was slower than during the second season. 

 At first the plants that gi-ew were few in number and kind. However, 

 it was easy to see that this state of affairs changed rapidly as the 

 first season advanced and new plants appeared more and more ciuickly. 



This was increased during the second year to such an extent that 

 at the expiration of the second season the whole area was densely 

 covered with plant forms, for the most part grasses of several kinds. 

 The grasses covered the area so completely that this tract of land was 

 cut over three times oefore the close of the second year. 



In the meantime the other forms, especially coarse and large weeds 

 were, for the most part, removed as their period of anthesis closed, 

 to prevent them from seeding, and also to record those that might dis- 

 appear. 



By the end of the first season 41 different forms had put in an 

 appearance on this area and reached maturity at or about the usual 

 time, as was determined by observing other plants of the same species 

 in the same locality. This, however, was not always the case, since 

 some of the same plants which were observed as controls near this area, 

 grew under more favorable soil conditions. Ulmus Americana put in 

 an appearance early. This was readily accounted for since some elm 

 trees of considerable size stood to the south of the area and about 75 

 feet away so that the winged seeds were easily carried by the wind. 

 This form grew vigorously and in some number, but not more so than 

 on the soil immediately surrounding this area. One specimen of Juglans 

 nigra was found which was evidently carried in thi'ough the agency 

 of some animal. Also two specimens of Carya ovata appeared the sec- 

 ond season. This, however, is easily accounted for by the presence 

 of a large ti-ee of this species a few feet away from this aiea, so that 

 a falling nut was readily transferred to this tract of land from this 

 short distance. 



Of all the forms that appeared on this area in the time noted the 

 representatives of the Gramineae were the most numerous. These and 

 other forms that grew here showed that wind, as would of course be 

 expected, was the most important disseminator of the plants recorded. 

 Of the 120 forms that were recorded by the writer and that appeared 

 in this area in the two years' observation almost 30 belonged to the 

 Gramineae. Not only did this family contain the greatest number of 

 forms, but also the greatest number of individuals. By the end of 

 the second year practically no difference could be a.scertained a short 

 distance away between this area and one that had been seeded for grass 

 for a much longer time. 



' Storer, cited by Woods, Alfred F., in the Yearbook of the Department of Agri- 

 culture, 1901, p. 165. 



