164 
NATURE NOTES. 
be carefully noted. Other foreign plants will be introduced 
accidentally, but after flourishing for one or two generations, 
will ultimately succumb ; yet others will continue to exist at one 
spot for a long while, and yet fail to spread to the neighbouring 
localities. All such cases may be looked out for, and recorded 
in the note books of the Society. 
As an example of the introduction of foreign plants, I maj' 
mention a case that came under my notice at Bedford Park. 
The people living next door to my home kept fowls in their back 
yard, which was, of course, very bare of vegetation. But after 
a while they left, and presently there sprung up a dense growth 
of plants of many kinds, covering the yard. I collected such of 
these as were unfamiliar to me (a good number) and took them 
to Mr. Baker at Kew, who was so kind as to look them over and 
tell me the names. They were south European weeds, the seeds 
of which must have come in the corn used to feed the poultry. 
Among them, conspicuously, was the pretty pink-flowered 
Sapomria Vaccaria, which I have since found similarly introduced 
in the Rocky Mountains. It is a plant which seems very 
readily introduced, but which has poor capacity for establishing 
itself permanently out of its natural range. 
Another interesting line of inquiry is that relating to the 
growth of plants on soil recently laid bare ; and this is very 
easily pursued near London, in railway cuttings, gravel pits, and 
a variety of other places. It will usually be found that in such 
situations there spring up some plants which are different from 
those of the surrounding fields ; these flourish for a while, but at 
length succumb, at least in most cases, to the inroads of the 
usual flora. 
Connected with this, is the problem as to seeds germinating 
which were supposed to have been long buried in the soil. It 
has been said that plants spring up in soil from some distance 
below the surface, owing to the presence of dormant seeds 
therein ; but while the fact of their springing up is not to be 
questioned, it is very far from being proved that the seeds were 
originally in the soil. It is easy to be mistaken on such a point, 
and experimental evidence is much needed. Some of the soil 
alleged to contain seeds should be carefully protected from all 
chance of receiving seeds blown by the wind or otherwise, and 
then if anything came up, the fact would have some weight in 
deciding the question. 
Turning now to the zoology, there is one curious matter that 
deserves special consideration. In the manufacturing districts 
of Yorkshire and Lancashire there has, during the last thirty 
years or so, been a remarkable development of melanism among 
the moths ; that is to say, several species of moths, usually 
brown or whitish, or variously marked, have lately come to pro- 
duce black or blackish varieties in great abundance, and these 
latter have in certain species come to actually outnumber the 
type. \’arious reasons have been suggested for this, such as the 
