370 ECOLOGY 



Yellow Rattle. The delicate roots of the last two species 

 are often attached to the roots of grasses, from which they 

 absorb part of their nutriment. 



At the lower level, where the soil is finer-grained, wetter, 

 and lies over a bed of shale, the plants are quite different. 

 The rolled-leaved grasses are displaced by grasses with 

 larger flat blades, such as Cock's Foot, Meadow Fescue, and 

 Yorkshire Fog, while flowering plants like Lesser Spearwort, 

 Ragwort, Knapweed, Lousewort, Yarrow, Red Campion 

 and Wood Betony occur. 



In a limestone pasture, however, species like Wild Thyme, 

 Yellow Violet, Lady's Fingers, Burnet, Yellow Bedstraw, 

 Small Scabious, Hoary Plantain, Blue Sesleria, Sheep's 

 Fescue-grass, and others are found. 



CHAPTER XXXI 



WATER AND MARSH PLANTS 



Vegetation of a pond. Examine the vegetation of 

 a pond or lake, and compare the plants of the banks with 

 those growing along the water's edge, and also with those 

 extending into the open water (Fig. 237). At the inlet, 

 look for the stages in the development of a marsh, and 

 notice how invasion of the pond takes place (Fig. 238). 

 Draw a transect, e. g. Fig. 239, through the pond, including 

 a portion of the bank, and show in a diagram the succession 

 of plants met with. The upper part of the bank (a) is 

 covered by meadow-species, but near the wetter soils be- 

 low (b), these give place to Rushes, Purple Loosestrife, 

 Water Dropwort, Iris, Marsh Marigold, Lady's Smock, 

 Large Bitter -cress, Bog Stitchwort, Ragged Robin, Meadow- 

 sweet, Lesser Spearwort, and Bog Starwort. 



Nearer the water's edge is a belt of reed-like plants (c), 



