0N THE MIXED HERBAGE OF PERMANENT MEADOW. 
1353 
percentage of nitrogen was relatively, indeed abnormally, high; or, in other words, 
less carbon was assimilated in proportion to the nitrogen accumulated. This might be 
due to a deficiency of available mineral matter, or to a limitation of the climatal 
characters for more active carbon assimilation, or partly to the one and partly to 
the other. 
These several points are considered in Part I. (pp. 327-332), and will be discussed 
in their chemical aspects in Part III. ; but an examination of the actual and compara¬ 
tive botanical characteristics of the plots will contribute useful data to the discussion. 
In Table LXXIII., pp. 1354-5, will be found for plot 11-1, with the mixed mineral 
manure and the double quantity of ammonia-salts each year (excepting in the fourth, 
fifth, and sixth), the percentage of each species at the different separations, the produce 
of each per acre, the increase of each over the unmanured plot 3, and also the increase 
over plot 9, with the mineral manure and the smaller quantity of ammonia-salts. 
With still more forced luxuriance than on plot 9, we have.at the same time a still 
greater reduction in the number of species. Taking the average of the four separation- 
years, we have, compared with the produce without manure, five fewer Graminese, three 
fewer Leguminosse, and as many as 22 fewer Miscellanese; or, in all, 30 fewer species. 
There was, indeed, on 11-1 an average of only 19 species against 49 without manure; 
and the number diminished in the four separation-years from 28 to 18, 16, and to 15 
only in 1877. Compared with plot 9 even, there was an average reduction of two 
Gramineae, one Leguminosse, and six Miscellanese : in all, of nine species. 
With the excessive luxuriance of individual species, and consequently greatly 
reduced numbers, the herbage is still more exclusively gramineous, the percentage of 
grasses reaching nearly 99 in 1872, and, on the average, nearly 95. Leguminosse 
were scarcely represented at all. Again, only three Miscellanese yielded more than 
1 per cent, to the produce in any one year, and these were the same as were persistent 
on plots 9 and 13, viz. : Rumex Acetosa , Conopodium denudatum and Achillea Mille¬ 
folium ; and they are in relative prominence in the same order as on those plots, but 
each in smaller and decreasing quantity. Thus, in the first separation-year there was 
more than 10 per cent, of total Miscellanese; in the second, not 6 ; in the third, little 
over 1 ; in the fourth, not 2^; and, on the average, only 5 per cent. 
Among the grasses, though considerably fluctuating in amount, and in much smaller 
quantity in the last separation-year than previously, Dactylis glomerata gave by far the 
highest average percentage in the produce. Indeed, in the second and third of the 
four years it contributed nearly 40 per cent., less than half as much in the fourth, and 
the general average was about 30 per cent. This plant was, in each separation-year, in 
very much higher proportion than on plot 9, with half the quantity of ammonia-salts. 
Next in order as to average percentage came Agrostis vulgaris ,. Holcus lanatus % 
Alopecurus pratensis, and Arena elatior ; each of which showed considerable tendency 
to increase, especially Agrostis , which in the fourth separation-year yielded nearly 
twice as much as the Dactylis, and has since maintained, perhaps, the first place 
among its competitors. Poa pratensis also yielded a fair average, but in the last 
