2\2 de Frame . — 7 ' he Morphology and Anatomy of the 
plants afford a striking instance of the luxuriance due to the temporarily 
improved conditions. 
Salisbury suggests that the remarkable increase in size of these over- 
whelmed plants is probably due to one of two causes, or to a combination 
of both. He attributes it to the freedom from competition which is pro- 
cured by the onflow of the pebbles, since the shingle kills most of the plants 
it covers, or else to the mulch action of the shingle on the buried soil, 
tending to increase its water-retaining power. 
The shingle, as such, is obviously not of value, for the lateral roots of the 
plants when dug up are found to be practically 
restricted to the soil beneath the covering layer, 
though they may also occur in the top layers 
where the soil and humus collect. 
In order to determine more exactly the 
effect of shingling on S. bmervosa , four experi- 
mental areas were started on the crest of a lateral 
shingle bank on the Marams in November, 1912. 
Patches of the bank about one yard in diameter 
were covered with loose shingle from the Main 
bank to a depth of 5 cm. In August, 1913, the 
areas were examined and in every case the 
characteristic plants had grown through the 
shingle covering, viz. Statice binervosa , Armenia 
maritima , Plant ago Coronopns , Obione portn- 
lacoides , and, in two of the patches only, 
Frankenia laevis. The plants of the covered 
patches showed a remarkable increase in luxuri- 
ance as compared with those of the surrounding 
bank ; not only were the rosettes more spreading, 
but the size of the individual leaves was much 
greater, the inflorescence axis much larger, and the 
flowering heads were distinctly more luxuriant. 
These features occurred not only in the case of 
Statice , but also in plants of Armenia and 
Plantago , and to a much less marked extent in Obione and Frankenia. 
Further, while practically all the plants of S. binervosa on the bank 
showed distinctly red coloration of the leaves, those of the covered 
patches were vividly green, with no trace of red. 
On removing plants of Statice and Armenia for examination, it was 
seen that all the leaves of the old rosette had died, and had been re- 
placed by a vigorous output of new leaves from one of the shoots of the 
rosette. 
After examination of the areas, three of the experimental patches 
Text-fig. i. Plant of Statice 
binervosa after shingling. x §. 
a, old dead rosette of leaves ; b, 
new rosette. 
