300 
THE JOURNAL OF BOTANY 
knowledge the abundance o£ well-preserved seeds which occur in these 
ancient deposits, and proved that the plants which now clothe our 
island abounded in very early times. On the Dogger Bank, in the 
middle of the German Ocean, a peaty deposit, known as “ moor log,” 
becomes entangled in the fishermen’s nets. In 1909 this deposit was 
carefully investigated by Mr. and Mrs. Reid ( Essex Naturalist , xvi. 
p. 54 ; 1909), who found that it was rich in well-preserved seeds, 
mostly of riverside and water plants, such as Alenyanthes trifoliata , 
all represented in our modern flora. 
Distribution. 
The mechanism by which individual seeds are distributed has been 
studied for a very long period and recorded in our text-books ; but it 
is only recently that the colonisation of new areas on a large scale 
has been receiving attention. The classical instance is that of the 
Island of Krakatoa, the vegetation of which was completely destroyed 
in 1883 by a volcanic eruption. The immigration of its new flora 
was studied by Treub (Ann. Jard. Bot. Buitenzorg. vii. 1888), who 
reported that within a brief period the island became covered with 
vegetation, consisting at first of algae, and soon almost entirely of 
ferns ; and within ten years a flora of phanerogams followed (Penzig 
in op. cit. 1902 ; Ernst, New Flora ... of Krakatau, Cambridge, 
1908). 
A recent experiment shows how well equipped seed-plants are for 
transferring themselves to new habitats (see Wheldon and Wilson, 
Flora of West Lancashire , 1907, p. 339; C. E. Moss, Vegetation of 
the Peak District, 1913, p. 159). A pond was made near Garstang 
in North Lancashire, and was carefully railed off against cattle ; it 
was watched to see what plants would appear in it: within eighteen 
months, Nitella opaca, Callitriche sp., Alisma Blantago , Glycerin 
fluitans , Juncus conglomeratus , and J. articulatus had established 
themselves. 
Some twenty-five years ago my attention was called by Mr. Tre- 
thewy, Lord Cowper’s land agent, to a small oak-plantation near 
Colchester, which had originated as follows:—A portion of a field 
had been railed in, to prevent people walking on the enclosed space 
and to protect it from rabbits; very soon a spontaneous and plentiful 
crop of young oak seedlings appeared m the space. There are sandy 
tracts in that part of Essex, which when fenced off soon develop into 
similar oak plantations. These are believed to arise from acorns 
dropped by the larger birds, such as pigeons and rooks, in flying 
from one plantation to another; rooks, indeed, have been observed to 
drop acorns. 
The influence of the soil in the alteration of a flora is to be seen 
near the brine springs at Droitwich, Worcestershire, and at North- 
wich, Cheshire, where the ground has become somewhat saline; the 
character of the flora has also changed and become maritime, as 
shown by the presence of halophytes, such as Atriplex glabriuscula 
var. Bahingtonii , Glaux maritima, Glycerin maritima , Juncus com- 
pressus var. Gerardi , and Spergularia salina (Lord de Tablev, 
