396 INVESTIGATION BY CULTURE EXPERIMENTS 



orders, there have been found of Gramineae (grasses) 20 species, of 5 genera; 

 of Leguminosae 10 species, of 5 genera; of Compositas 13 species, of 12 genera; 

 of Umbelliferae 5 species, of 5 genera; of Polygonacese 3 species, of i genus; 

 of Ranunculacese 5 species, of i genus; and of Plantaginaceae 2 species, of i 

 genus. The majority of the 22 orders are, however, represented by only one, 

 two, or three species, and only one genus each. To take an example, it may 

 be stated that the herbage of the unmanured plot comprises about 50 species, 

 and that any kind of manure that is, anything that increases the growth of 

 any species induces a struggle, greater or less in degree, causing a greater 

 or less diminution, or a disappearance, of some other species; until on some 

 plots, and in some seasons, not more than 15 species have been observable; 

 indeed, on some, after a number of years, no more than this are ever traceable." 



Director Hall reports that in 1903 about 97 per cent of the prod- 

 uce from plot n-i (ammonium salts and minerals) consisted of 

 three species: false oat grass (Arrhenatherum avenaceum), 

 meadow foxtail (Alopecurus pratensis), and meadow soft grass 

 (Holcus lanatus}. On plot 14, which receives nitrate and minerals, 

 the herbage is quite similar except that about 45 per cent of meadow 

 soft grass is replaced by 23 per cent of soft brome grass (Bromus 

 mollis}, 9 per cent of blue grass (Poa pratensis}, 3 per cent of 

 meadow pea (Lathyrus pratensis}, and 10 per cent of wild beaked 

 parsley (Anthriscus sylvestris}, a weed practically never found 

 on any other plot. 



The herbage of plot 7 (minerals) in 1903 included 4.27 per cent 

 of white clover, 6.41 per cent of red clover, .43 per cent of bird-foot 

 trefoil (Lotus corniculatus} , and 22.04 P er cent of meadow pea; 

 while plot 8 (minerals except potassium) showed 1.25 per cent of 

 white clover, 1.38 per cent of red clover, 12.24 P er cen t of bird-foot 

 trefoil, and 3. 70 per cent of meadow pea. Yarrow (Achittea mille- 

 folium) is a common weed (i to 10 per cent) on plots 6, 7, 8, and 15. 



The produce of plot 6 (changed from ammonium salts to min- 

 erals in 1869) contained sorrel (Rumex acetosa} to the extent of 

 12. 1 1 per cent in 1862 and 24.27 per cent in 1867, which dropped 

 to 7.51 percent in 1872 and to 5.24 per cent in 1903. Plot 5 showed 

 14.84 per cent of sorrel in 1903. Lance-leaf plantain was found to 

 the extent of 1.98 per cent on plot 3 (unfertilized), 2.49 per cent 

 on plot 4-1 (acid phosphate), 5.85 per cent on plot 8 (minerals 

 except potassium), and 10.70 per cent on plot 17 (sodium nitrate), 

 in 1903. 



