288 Yapp. —On Stratification in the Vegetation of a 
R <— D 
WATER LEVEL 
Text-Fig. 4. Diagrammatic section through ‘ Sedge’ vegetation, showing stratification 
of both shoots and roots. The field sketch was made on a windy day (August 15, 1907). Note 
that the direct effect of the wind is confined to the upper strata. The instruments (A, B, C and D) 
are as arranged for the August and September Experiments, 1907. 1 2 
Cl. Cladium (5) 2 ; H. Hydrocotyle (1) ; L. Lythrum ; M. Molinia ; P. Phrag mites (4) ; 
Sp. Spiraea (3) ; Sy. Symphytum ; Th. Thalictrum (young). x Tt>* 
1 N.B. Though here shown vertically over one another, each set of instruments was really 
arranged at an angle with the others. 
2 The numbers in brackets after plant-names refer to the ecological type of habit (see p. 277). 
