ON THE STBUGGLE FOE EXISTENCE AMONGST PLANTS. 135 
counties are indigenous at all ; nay, more, I have been tempted 
to suspect that some of the more variable of them, as some 
species of chenopodium and fumitory, may have originated since 
cultivation began. In the uncultivated counties, the proportion 
of annual plants is exceedingly small, whereas, in the cultivated 
counties, annuals are very numerous ; and the further we go from 
cultivation, roads, and made-ground, the rarer they become, till 
at last, in the uninhabited islets of the west coast of Scotland, 
and in its mountainous glens, annuals are extremely rare, and 
confined to the immediate vicinity of cottages. Let any one 
who doubts this contrast between the Floras of cultivated and 
uncultivated regions compare the annuals in such Florae as those 
of Suffolk or Essex, the North Riding or Cumberland, with those 
of the Isle of Wight and the Isle of Arran. And it is not only 
that annuals abound in the cultivated districts, but that so 
many are nearly confined to ground that is annually or fre- 
quently disturbed. The three commonest of all British plants, 
for example, are, perhaps, groundsel, shepherd’s purse, and 
Poa annua . I do not remember ever having seen any of these 
plants established where the soil was undisturbed, or where, 
if undisturbed, they had not been obviously brought by man, or 
the lower animals ; and yet I have gathered one of these, the 
shepherd’s purse, in various parts of Europe, in Syria, in the 
Himalayas, in Australia, New Zealand, and the Falkland Islands. 
Were England to be depopulated, I believe that in a very few 
years these plants, and a large proportion of our common 
annual “ wild flowers,” would become exceedingly rare, or ex- 
tinct, such as the Poppies, Fumatories, Trefoils, Fedias, various 
species of Speedwell, Anagallis, Cerastiums, Lithospermum, 
Polygonum, Mallow, Euphorbia, Thlaspi, Senebiera, Medicago, 
Anthemis, Centaurea, Linaria, Lamium, &c., &c. 
It is usually said of some of the above named plants, that they 
prefer cultivated ground, nitrogenous soil, and so forth; and 
this is no doubt true, but that they will flourish where no such 
i advantages attend them, a very little observation shows; and 
that they do not continue to flourish elsewhere is due mainly 
to the fact that, being annuals, their room is taken as soon as 
they die, and the next year’s seedling has no chance of success 
in the struggle with perennials. 
For good instances of this rapid replacement of annuals by 
perennials, the new railroad embankments should be examined. 
Whence the plants come from, which spring up like magic in the 
\ cuttings, many feet below the surface of the soil, is a complete 
mystery, and reminds us of the so-called spontaneous generation 
of protozoa in newly-made infusions, or in distilled water. In 
the south of Scotland in 1840-50, and many parts of the north of 
i England, the first plant that made its appearance was Equisetum 
VOL. VI. — NO. XXIII. M 
