Jan. 1901.] BOTANICAL SOCIETY OF EDINBURGH 25 



the usual crofter " lazy bed " system, and are thrown into 

 rivers or on the shore after field weeding. Stdlaria media 

 can only keep permanent hold in places with little competi- 

 tion, as on shores and floors of caves, or by frequent renewal 

 by being in places much resorted to by animals. It is one 

 of the species that can be traced on moors on the dung of 

 cattle. Ranunculus repens is almost confined to ground 

 that has been disturbed by plough or spade. It does not 

 retain its hold for many years on ground that has originally 

 been pasture. Its most permanent position is perhaps by 

 roadside ditches ; these are of course occasionally cleaned, 

 and the plant does not spread any distance beyond the 

 disturbed ground. Of weeds as introductions of last century, 

 the most noticeable is Veronica Buxhaumii, which Watson 

 considered as having been introduced into Britain about 

 1825. It is still an uncommon plant on the coast. In two 

 instances I have known it having made its first appearance 

 in gardens, not in cornfields, but it is in the former locality 

 that its appearance would be most readily observed. Jiincus 

 tenuis is a conspicuous introduction of late years. It is 

 perhaps not sufficiently known to have been often recog- 

 nised, but as it occurs in three localities with which I am 

 familiar, it most probably is to be found in others. It 

 appears so far to retain its hold when once introduced. 

 The same cannot be yet said of Potentilla Norvegica, of 

 which there is evidence of its increasing appearance on 

 this coast. 



Before the introduction of haymaking in the West 

 Highlands, about the year 1756, no attention was paid to 

 the kind of grass in fields, and it could only be on the 

 introduction of ryegrass and clover that the plants formerly 

 mentioned as occurring in sown grass fields would be intro- 

 duced. AlojKCurus pratensis, Phleum p)r (dense , Poa nemoralis, 

 are also evident introductions to some parts through this 

 means, as well as an increased distribution, if not the 

 introduction, of Bromus mollis, B. commutatus, and B. seca- 

 linus. B. mollis spreads from cultivated fields along bare 

 places by roadsides, and it occasionally reaches sandy shores, 

 when it usually becomes dwarfed. B. commutatus is a much 

 rarer plant, and remains local in its distribution ; while 

 B. sccalinus appears to be hardly more than a casual. 



