A *‘shell-hole flora” as a result of the World War 
WALTER SCHWARZ 
Who can ever forget the impression of senselessly destroyed 
life in the Argonne forests? For long stretches there were stand- 
ing only tree stumps splintered by shells. Here and there some 
little green leaf showed itself. One could not get rid of the sad 
impression created by a pine-wood destroyed by poison gas, 
where the needles, brown and dry, hung on the branches. But 
scarcely were the ruined woods out of the direct fire zone, than 
a quite novel kind of flora suddenly sprang up. Here grew the 
delicate red blossoms of the Rosebay (Epilobium angustifolium) 
the tiny yellow heads of the Groundsel (Senecio sylvaticus) and 
other sun loving plants which are ordinarily only found in places 
where the trees have been felled. Here they got the upperhand, 
as the shade giving tree tops had disappeared. Even the deep 
shell-holes, soon after their formation, became the home of a 
new plant world. Splendid green algae flourished in the water 
collected in the bottoms. The sides immediately above the water 
surface were covered with moss. Higher up towards the edges 
flowering plants appeared. The conspicuous thing about these 
plants was that they were not previously found in the imme- 
diate neighbourhood. A plant society peculiar to these holes 
had been formed, a shell-hole flora. The conditions of life for the 
plants in the holes were quite different from those outside. Here 
there was greater moisture and changed light conditions. Only 
such plants could develop as were adapted to the new con- 
ditions. A natural selection in miniature had taken place. Even 
inside a single hole differences in colonization showed them- 
selves. The side exposed to the morning sun was overgrown 
with plants different from those on the flank enjoying the after- 
noon sun, 
Particularly interesting were the conditions where arable 
land had been ploughed through by shells. After the fighting 
zone had shifted, a new vegetation cover developed. Then the 
superiority of the wild flowers over those cultivated by man 
with so much care, showed itself. Everything was overgrown 
with magnificent red poppy, with luxuriant white Chamomile 
(Matricaria inodora and M. discoides) and red thistle (Cirsium 
arvense). Only here and there could there be found traces of the 
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