818 THE JOURNAL OF BOTANY 
two-thirds of its length by a line of sand-dunes nowhere at 
ten feet in height or : hundred yards in extension inland, and fixed 
by a luxuriant growth of Psamma arenaria. The greater of 
the Anes is ig a and much of it is submerged at high ti 
On careful examination of the Bull in September, 1894, 
eight x8 patches. of the Artemisia were found, distributed over a 
length of some six hundred yards, each patch being about a yard in 
diameter. All of the patches were confine = to the dunes on the 
eastern or seaward side of the bank, e being observed at a 
distance of more than twenty yards APOE from the seaward crest 
of the dunes, while one grew on the crest itself. In 1896 a per- 
ceptible increase of the plant was noticed, - in 1898 a still 
further i increase, accompan ied by a movement eastward or seaward, 
one patch having quite creased the dunes a "cesta the beach 
outside, while another had gained the top of the crest. No further 
well as increase of mass. hereas previously the extreme length 
ae by the widely separated patches from south to north was 
e 600 yards, the range this year extended for fully a mile. At 
ay as noticeable as the great increase of the plant was the 
general north-eastward drift it appeared to have made from the 
position occupied by the first settlement observed in 1894. The 
effect of this drift—using that word, of course, in a — re dpe 
sense—has been to transport the plant (all, save a few small 
patches) across ef dunes to the sea-beach forming she pr 
margin of the 7 Gavite left behind it the zone of Psamma 
arenaria, it has invaded that of Triticum junceum, and, firmly 
established here, ‘shrestetis soon to dispute with Salsola and with 
Atriplex Babingtonii and A. farinosa the possession of that iad zone 
of terrestrial vegetation which lies immediately above tide-m 
This north-eastward drift should, no doubt, be attributed 0 the 
influence of the prevailing west a nd south-west storm-winds. By 
these winds the brittle stems res shoots of the mature plants are 
torn off in late autumn and winter and carried eastward or north- 
Artemisia Steller ill be swept off the sand-bank into Dublin 
Bay? ‘The fact that the plant in its new position is sheltered by 
the ay satire rom the reer storm-winds gives us reason to 
