II] WOODLAND ASSOCIATIONS 77 



Melampyrum sylvaticum, and Cypripedium Calceolus are 

 examples, though, judging from an old record, cited in Linton's 

 flora (1903 : 274), the last-named species seems to have occurred 

 formerly in Derbyshire. 



The following plants are found in ash woods of Derbyshire, 

 but do not occur so far south as Somerset, and are hence absent 

 from woods of the ash type in the latter locality : 



Stellaria nemorum Campanula latifolia 



Cardamine amara Cnicus heterophyllus 



Trollius europaeus Melica nutans 



Geranium sylvaticum Festuca sylvatica 



Polemonium coeruleum Hordeum sylvaticum 



Myosotis sylvatica Carex ornithopoda 



On the other hand, the following plants occur in woods of 

 the ash type in Somerset, but have not been noticed during the 

 present survey in those of the hills of the Peak District : 



Clematis Vitalba Viburnum Lantana 



Aconitum Napellus Calamagrostis Epigejos 



Euphorbia pilosa Colchicum autumnale 



E. amygdaloides Cephalanthera grandiflora 



Lithospermum purpureo-coeruleum Ornithogalum pyrenaicum 



The autumn saffron (Colchicum autumnale) is indigenous in 

 pastures on the Permian limestone; but it is not a woodland 

 plant in the north of England, as it is in Somerset and 

 Cambridgeshire. 



The following lime-loving and shade-loving species occur on 

 the lowland Permian limestone tract to the east of the Pennines, 

 but are absent from the woods of the Carboniferous Limestone 

 of the Peak District : 



Astragalus glycyphyllos Viburnum Lantana 



Galium MoUugo Calamagrostis Epigejos 



Generally, it is clear that the ash woods occurring on the 

 calcareous soils of England are richer in species than the oak 

 and birch woods occurring on the non-calcareous soils, and that 

 of species common to both types of wood, many are more 

 abundant and ascend to higher altitudes there than in the oak 

 and birch woods. These facts can scarcely be held to support 

 a statement sometimes made that calcium carbonate acts 

 deleteriously on plants. Woodhead (1906 : 396) states that 

 his study of the woods around Huddersfield " indicates that in 



