1270 MESSRS. J. B. LAWES, J. H. GILBERT, AND M. T. MASTERS, 
In the second separation-year, 1867, when it reached its highest amounts, it was 
most productive on the two plots 9 and 13 highly dressed with both mineral manure 
and ammonia-salts, and on plot 7, with the mixed mineral manure, including 
potash, but without ammonia. It is obvious that this plant can, probably by reason 
of its tuber, and its thin stems which are not overpowered by the grasses, sustain the 
competition of free-growing grasses, even when these latter are stimulated by ammonia- 
salts in conjunction with mineral manures; but a liberal supply of the latter would 
seem to be essential to its luxuriance. It is apparently much less favoured by nitrate 
of soda than by ammonia-salts. The table shows that it occurred in very much less 
amount in the third and fourth separation-years; although in some seasons it has been 
very conspicuous on many plots. During the three years (1878, 1879, 1880) it was 
estimated to be either first, second, or third in order on the unmanured plots, and on 
those treated with ammonia-salts. On plot 9 (minerals and ammonia) it has been 
conspicuous and abundant, but with the minerals and the double quantity of ammonia 
(plot 11) it has not thriven; and during the three years above-mentioned it has 
occurred very rarely on this plot—but abundantly on plot 20, with the nitrate of 
potass and superphosphate. 
With regard to the great development of this plant in 1867, it may be observed 
that it corresponded nearly with that of Rumex Acetosa in the same season. Perhaps 
the relatively low spring rainfall and temperature of that season may have discouraged 
the growth of the grasses, and thereby allowed of the superior growth of Conopodium, 
Rumex, and other miscellaneous plants. 
Pimpinella Sctxifraga. 
This has a short, stout stock, rather slender, erect stems, and pinnately divided 
broad leaves. It was found in the samples from almost all the plots, excepting those 
liberally manured with ammonia-salts, from which it was frequently absent. It was 
also in very small amount in the samples from the nitrate plots; and it was the most 
prominent on the unmanured plots, and on those receiving an only partial mineral 
manure. Excepting that it was more prominent in the second than in either of the 
other separation-years, it may be said to have gone down, even on the plots the most 
favourable to it; and it has done so more markedly on the unmanured plots, than on 
the one treated with superphosphate of lime alone. It is obvious that this Umbellifer 
is not able to hold its own under the influence of nitrogenous manures, whether alone 
or in conjunction with mineral manures, that is under conditions which favour the 
grasses, nor when mineral manures are used alone, in which case the luxuriance of 
Leguminosse, and other plants, is promoted. 
Heracleum Sphondylium. 
This is a tall, coarse-growing plant, with very large, thick, fleshy, deeply-penetrating 
root-fibres, and broad rough foliage. It is a biennial, and occurs generally in isolated 
