O INTRODUCTION. 



Sandy strata present in general a suite of peculiar 

 plants, or those at least as luxuriate best in such a 

 soil, while there are very local ones, as Tillcsa muscosa, 

 and Veronica verna and trypliyllos, which are only 

 found in such situations. The following are observed 



to prefer sandy commons and fields. 



Turritis glabra 

 Teesdalia nudicaulis 

 Silene Otites 

 Silene conica 

 Silene Anglica 

 Arenaria peploides 



rubra 



Radiola millegrana 

 Erodium cicutarium 

 Trifolium suffocatum 



scabrum 



Trifolium striatum 



arvense 



Jasione montana 

 Centunculus minimus 

 Lamium amplexicaule 

 Scleranthus annuus 

 Phleum arenarium 

 Festuca Myurus 

 Elymus arenarius 

 Carex arenaria 



Many plants are common to several rocks and soils, 

 and therefore it is chiefly upon isolated hills and 

 elevated summits, where nature retains its pristine 

 aspect, and where cultivation has not penetrated, that 

 the mineralogical condition given to the formation, 

 exercises the most material influence in determining 

 the existence of particular plants. It might be con- 

 sequently expected that granitic and igneous rocks 

 would have some characteristic plants, independent of 

 their altitudinal character. But as secondary and ter- 

 tiary strata, as well as diluvial gravel, are nothing 

 more than modified ancient rocks, this is not so much 

 the case as might be imagined, and many species are 

 equally found upon igneous rocks and on gravel. So 

 several conspicuous plants often growing on granitic 

 or basaltic heights, occur also on calcareous rocks, as 

 Veronica spicata, which is abundant on the Brithen 



