CX11 PROCEEDINGS-PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
V. dentata , Poll.—A rare weed of cultivation. 
Dipsacus sylvestris , L.—Since this is confined (except on bal¬ 
last heaps) to Kinnoull Hill it is not above suspicion, especially 
since some plants which are regarded as aliens grow on that hill. On 
the other hand, the warm shelter afforded by the escarpments of trap 
rock present a suitable habitat for species attaining in this latitude 
their northern limit. Hence the Teasel is not necessarily to be 
classed as an introduction. 
Bidens tripartita , L.—Whilst there is no reason for supposing this 
to be an introduction, as it is not a plant likely to be introduced by 
human agency, there are few, if any, places in Perthshire where one 
can go with any certainty of finding it two years in succession. 
Possibly its sporadic appearances may be due to a fruit or two being 
brought by water-fowl, or perhaps the seeds lie dormant and germi¬ 
nate irregularly. 
Anthemis arvensis , L.—“A colonist” (Watson). 
A. Cotula , L.—A rare casual. 
Matricaria inodora , L.—Most frequently a weed of cultivation, 
but has some claim to be considered native. It is, of course, native 
on the sea-shore. 
Chrysazithemum segetum, L.—A weed of cultivation. 
C. Parthenium , Pers.—Watson calls this a denizen; and Hooker 
says, “probably naturalized only.” With us it is certainly an intro¬ 
duction. 
Tanacetum vulgare , L.—“Probably naturalized only” (Hooker). 
This is so abundant on the banks of the Tay, and some of its 
tributaries, that it is not quite clear that it may not be native. 
Whilst, on the one hand, it is a species which was formerly used for 
medicinal and culinary purposes, and is, moreover, a plant which 
spreads rapidly, on the other, it must be remembered that because 
a plant has useful qualities it is not therefore necessarily an intro¬ 
duction, and that the distribution of the species extends to Arctic 
Europe. 
Artemisia vulgaris , L.—In hedgebanks and near houses, widely 
spread, but never very common. I entertain little doubt but that 
this is an introduction. It was formerly used to flavour drinks. 
Senecio viscosus , L.—Near Perth this is a comparatively recent 
introduction with railway ballast. Possibly nearer the sea, as at 
Invergowrie, it may be native, but I think not. 
S. vulgaris , L.—A weed of cultivation, and mostly in garden 
ground. 
Centaurea Cyanus , L.—A weed of cultivation. 
Carduus uuta?is, L.—In one field near Blairgowrie, where it must 
have been accidentally introduced. 
Cichorium Intybus , L.—Only a rare casual. 
