ON THE MIXED HERBAGE OE PERMANENT MEADOW. 
1239 
occasions third; once on the plot then receiving farm-yard manure, once with super¬ 
phosphate of lime alone, and once with the complete mixed mineral manure alone, but 
once also with the larger amount of nitrate of soda and the mixed mineral manure. 
It contributed more than 5 per cent, to the produce six times in the first separation 
year, only four times in the second, eight in the third, and only twice in the fourth. 
The conditions under which it has most conspicuously maintained its position are where 
both nitrate of soda and mineral manure was employed. 
It attained to between 11 and 12 per cent, in 1872 on the plot which had formerly 
received farm-yard manure, and it reached nearly 19 per cent, in the same year, on the 
plot with the mineral manure and the smaller amount of nitrate of soda. On no other 
plot has it shown any marked prominence. 
Of the three species of Avena, A. elatior is the only one that may be said to have 
gained ground on the experimental plots; and it has done so were there was liberal 
nitrogenous manuring, in the form of ammonia-salt, with mineral manure in addition. 
Both A. pubescens and A. Jlavescens have, on the other hand, gone down ; and neither 
of them has maintained even moderate prominence where ammonia-salts were used ; 
but both, and especially A. Jlavescens, have been more favoured under the influence of 
the nitrate. 
The comparatively robust habit and superior physical endowments of A. elatior are 
sufficient to account for its superiority over its congeners when growing in association. 
It may here be remarked that many botanists place A. elatior in a distinct genus— 
Arrhenatherum, by reason of the lower flower of each spikelet being male only, and 
also from the presence of certain rudimentary organs, indicative of a different line of 
descent of this plant from the true Avenas. 
Poa trivialis. 
This plant has closely matted minute fibrous roots, not penetrating deeply, but 
forming a dense mat beneath the surface, producing no underground offshoots, but 
developing, especially in moist weather, creeping branches from the base of the culms. 
The culms are tufted, 1 to 2 feet in height, rather rough, and bear linear leaves, 
narrower than those of P. pratensis. It is early in growth, though rather tender, and 
liable to injury from frost or drought. It grows rapidly, flowers in June, and again 
in the autumn. It seeds abundantly in the first crop, especially on plot 14 (mineral 
and high nitrate), where numerous seedlings have been observed. Like P. pratensis it 
prefers a moist rich soil. 
The endowments propitious to the growth of this plant are its dense root-develop¬ 
ment, its rapid growth under favourable conditions as to soil, manure, and moisture, 
its formation of stolons, and its free seeding tendency. 
Table XLIY. registers its characters as to predominance. 
7 t 2 
