Sub-associations of the Grownd Yegetation 151 



(2) Other parts of the woods, which, though not 

 marshy, are nearly always very moist, have a rich and 

 varied ground flora. Sheets of wood-garlic (Allium 

 ursinum) (Plate XIII b) and of the lesser celandine 

 {Ranunculus Ficaria) are characteristic. The following 

 is a selected list of the species of such damp parts of the 

 ashwoods : 



(3) On soils which are drier than the preceding, and 

 which, during the summer months, may become tem- 

 porarily very dry, sheets of dog's mercury (Mercurialis 

 perennis) often occur; and this plant is in Derbyshire very 

 frequently associated with the moschatel (Adoxa Mos- 

 chatellina). At the beginning of April, in the Derbyshire 

 dales, the dog's mercury is about three inches high, its 

 leaves are beginning to unfold, and a few stamens are 

 ripe. At this time of the year, the moschatel is here 

 flowering abundantly, and is almost hidden by the young 

 shoots of the dog's mercury. In the fairly dry portions 

 of the ashwoods of the Peak district, this plant society of 

 dog's mercury and moschatel is a characteristic feature. 

 The society is an excellent example of what Woodhead 

 (1906, p. 345) terms a " complementary " society, as the 

 roots of the dog's mercury reach down to lower layers 

 of soil than the roots of the moschatel, whilst the small 



