22 ALIEN FLORA OF BRITAIN 



Isatis tiuctoria, L. Apparently native^in South-East 

 Russia, where Korshinsky recorded it growing, as a 

 native, on exposed hillsides and in bushy places. Its 

 cultivation from the earliest times has led to its 

 occasional appearance in an apparently spontaneous 

 state in other parts of Europe, including England. It 

 is one of those species which occasionally appears in 

 plenty when ground is newly turned, doubtless on the 

 site of former woad-crops, from which stragglers have 

 persisted and seeded from time to time, until some 

 fortuitous disturbance of the ground has given the 

 seeds a chance of germinating. 



Lepidium campestre, R. Br. A plant of roadsides, 

 cultivated and waste ground, throughout Europe and 

 North America. In England it has long been known 

 as a plentiful weed in ground unintentionally prepared 

 by man, but it is nowhere known in this country, or 

 elsewhere, in perfectly natural habitats. It is possible 

 that it is a derivative of the wild Lepidium hirtmn, its 

 annual habit and other distinctive characters having 

 resulted from adaptation to agricultural surroundings. 



Lepidium coronopifolium, Fisch. Probably a native 

 of Persia and Turkestan. A frequent weed in parts of 

 Eastern Europe, and once recorded as a casual in 

 England. 



Lepidium Draba, L. Native of dry sterile ground in 

 South-East Europe, and Western Asia, being especially 

 abundant in the deserts of the Caspian region. Though 

 apparently only introduced into Britain in the early part 

 of the nineteenth century, it has now become a not 

 infrequent weed on rubbishy ground, on railway and 



