CIV PROCEEDINGS—PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
duced by human agency, directly or indirectly. Every plant must, 
however, be judged on its own merits. 
Let us now examine in detail all the constituents of the Perth¬ 
shire phanerogamous flora which are not unanimously admitted to be 
natives, excluding from our examination, of course, all those which 
are indubitably aliens. In selecting the species whose claims to 
a position as natives have to be considered, I have followed Watson 
in his various works on British plants, and Sir J. D. Hooker in the 
“ Student’s Flora,” both of whom have given opinions on the subject. 
In addition, I have, however, included a number of species of whose 
right to be considered natives of Perthshire, Perthshire botanists are 
probably the best judges. In this way the list that I have compiled 
embraces no less than 143 species, which may be divided into the 
following classes or groups :—(1) casual aliens; (2) naturalized aliens; 
(3) probably introduced; (4) roadside and hedgebank plants; 
(5) colonists; (6) probably natives; (7) certainly natives. 
1. Casual Aliens. 
By “ alien,” in this and the following group, is meant a species 
which is an alien (/.<?., certainly or presumably introduced by the 
agency of man) in Perthshire , but not necessarily in Britain , since 
some of them are admittedly native in England. If all the aliens of 
our flora had been enumerated, a very long list might have been 
drawn up; as it is, those only are included regarding whose position 
there has been some uncertainty. A casual alien is a plant which 
only occurs sporadically, or is at the best a garden outcast which 
barely maintains its position. A ? after the name signifies that it is 
with some doubt that the species has been placed in this group. 
More details regarding the species in this and the following groups 
are given in the Appendix, in which, for the sake of convenience, the 
species are not grouped, but taken in their ordinal arrangement. (7) 
Berberis vulgaris. 
Brassica alba ? 
Malva sylvestris. 
Melilotus altissima. 
Anthemis Cotula. 
Cichorium Intybus. 
Arnoseris pusilla. 
2. Naturalized Aliens. 
Naturalized aliens are species which not only maintain their 
position, but spread, some of them to a considerable extent. Some 
of the plants in the list are not natives of Britain, but have been 
included because doubt has been expressed as regards their naturaliza¬ 
tion even. (14) 
Chelidonium majus. 
Cheiranthus Cheiri. 
Hesperis matronalis. 
Geranium perenne. 
Carum Carui. 
Sambucus Ebulus. 
Chrysanthemum Parthenium. 
Senecio viscosus. 
Carduus nutans. 
Lactuca muralis. 
Chenopodium Bonus-Henricus. 
Salix alba ? 
Arum maculatum. 
Lemma trisulca. 
