62 
Conceiving a time previous to the advent of cultivation, there 
would have been here, on one side, the unbroken turf of the Downs, 
with its crowded occupants, in possession of the soil from the remotest 
antiquity ; on the other side, the sea, with its continually shifting 
vegetation, ever seeking the new ground there supplied to it. 
Turning now to the cultivated land, we found on every side a pro- 
fusion of plants, which, in defiance of the most strenuous exertions, 
kept their footing in the soil, ready to become rampant with the least 
remission of human industry. Familiar examples of these plants 
were Convolvulus arvensis, all the poppies, Sonchus, Sinapis alba, and 
S. arvensis, Euphorbia peplus, E. exigua, and E. helioscopia, Mercurialis 
annua, and Triticum repens. That all these plants were now in occupa- 
tion of the cultivated ground solely through the favourable conditions 
which cultivation supplied to them, seemed evident when we considered 
their requirements, which appeared to be moved or broken earth, and 
sufficient open space ; for none of these plants, not even the Convolvu- 
lus and the Triticum, were able to establish themselves in the turf of 
the Downs, and as they were not plants capable of existing in woods, © 
or in marshes, he begged to submit to their consideration the hypothe- 
sis that all these plants had migrated inland from the sea coast, where 
alone the necessary conditions required for their growth were originally 
by nature provided for them. 
Few papers read before the Society elicited so much information 
from the Lecturer, and from the gentlemen who took part in the 
discussion. Among the various topics discussed were; What is a 
species }—the vitality of seeds, the tendency of strong and robust 
plants to destroy the weak and feeble, springing from seeds from the 
same seed vessel ; the marvellous variety of the general characters 
often observable in plants of the same kind, grown from the same 
seed, and under the same conditions ; the curious and extraordinary 
growth of plants new to the locality, after drainage, breaking up the 
soil, or fires ; the alteration in some of the qualities of plants, by care- 
ful selection of seed and high cultivation ; the advantages derived from 
careful selection of seed, &c, These, as well as other points thrown 
down in the paper, were discussed by the President, and Messrs, 
Mitten, Glaisyer, C. P. Smith, G. Davies, Wonfor, Hennah, G. Scott, 
B, Lomax, Nourse, and Sewell ; and a hearty vote of thanks was given 
to Mr. Mitten for his paper. 
