THE BATTLE OF LIFE AMONG PLANTS. 
39 
Foresters in all countries are perfectly well aware of these 
facts, and botanists watch with interest the appearance of a 
different vegetation, when some accident has interfered with 
the previously existing conditions. When woods are cut down, 
when soil from a depth is laid on the surface, when extensive 
fires occur, when lakes are drained ; in fact, when any sudden 
alteration takes place in external circumstances, then we may 
expect to find a corresponding change in the vegetation. One 
set of plants profits by the change, another suffers. It may be 
asked, “ Where do the new arrivals come from ? ” Some- 
times, no doubt, the seeds are wafted from a distance, and, 
finding a suitable abiding-place, germinate. This is, perhaps, 
more especially the case with the spores of fungi, whose ex- 
treme minuteness favours their dispersion in this way. But it 
often happens that the facts of the case will not admit of such 
an interpretation, and then we can only fall back on the sup- 
position that the seeds or bulbs existed in the soil, but under 
circumstances not favourable to their development. 
The ground in this way is looked on by Alphonse de Can- 
dolle and Darwin as a vast magazine of seeds, &c., capable of 
retaining their vitality for a more or less prolonged period, 
according to circumstances, and ready to avail themselves of 
any change that may be beneficial to them. That this is so in 
some places has been proved by results, but it seems equally 
clear that this does not hold good in all places. Allusion has 
already been made to the apparently capricious appearance of 
our British orchids. The downs or the fields that in one 
summer yielded abundance of bee, of fly, or of spider orchids, 
may, in another year, scarcely furnish a single one. The ex- 
planation of this peculiarity lies in the special organisation of 
the plant well described by Prillieux and other botanists, from 
whose observations it appears that the plants in question 
naturally pass through several stages, which, for our present 
purpose, it is not necessary to detail, and these stages may be 
prolonged according to circumstances. The flowering stage is 
thus arrived at in one season, while in another all the energies 
of the plant may be taken up in forming tubers and leaves. A 
very remarkable instance of the fact just alluded to was com- 
municated to the writer by a competent observer, Mr. George 
Oxenden, of Broome Park, Kent. This gentleman had been 
acquainted with a particular field for some forty years, during 
which time it had been under the plough, but at the expiration 
of this period it was laid down in grass, when the very next 
year a profusion of bee orchids was observed in it. In this 
case the time was too short for seeds to have germinated and to 
have progressed to the flowering state. There seems no other 
solution than that the tubers must have been in the ground 
