216 BRITISH PLANTS 
or disturbed ground, or in waste places near it, and 
seldom, if ever, anywhere else. They are all aliens, 
although many of them are so common and widespread 
that they are generally regarded as native. Of these 
long-established aliens, found only in artificial habitats, 
the following are the most familiar : 
Poppies, wild radish, corn-cockle, common vetch (Vicia 
sativa), shepherd’s-needle, sweet cicely, chicory, milk- 
thistle, corn-bluebottle (Centaurea Cyanus), the Canadian 
fleabane (Hrigeron canadense), chamomile, the fumitories 
and brassicas, most of the chenopodiums, some spurges, 
ivy-leaved toadflax, Geranium pusillum, Veronica agrestis, 
V. arvensis, Lycopsis arvensis, Verbena officinalis, black 
horehound (Ballota nigra), pennycress (Thlaspi arvense), 
white lychnis (Lychnis vespertina), Cerastiwm arvense, the 
common mallow (Malva sylvestris), melilot, goutweed 
Agovodium Podagraria), fool’s-parsley (Aithusa cyna- 
pium), corn-marigold (Chrysanthemum segetum), the corn- 
campanula (Campanula hybrida), Stachys arvensis, Urtica 
urens, the slender fox-tail grass (Alopecurus agrestis), 
Bromus arvensis, and even such common and universal 
weeds as shepherd’s-purse, treacle-mustard, common 
nightshade (Solanum nigrum), charlock (Sinapis arvensis), 
sow-thistle (Sonchus arvensis), the white and red dead- 
nettles (Lamium album and purpureum), and possibly also 
the common stinging-nettle (Urtica dioica). 
It is interesting to observe in how many cases the 
specific name indicates the nature of the plant as a weed 
of cultivation—e.g., arvensis = belonging to the ploughed 
field, agrestis=belonging to cultivated ground, sativus 
and segetum=sown. Most, if not all, these plants came 
in the track of cultivation from Asia as it spread gradually 
westwards—first through the Mediterranean region, and 
then over northern Europe. Many of them have 
naturally found their way to the New World, and even 
to our distant colonies. 
