722 



This beautiful species occurs in almost every county of England, 

 but more abundantly in the neighbourhood of London than in other 

 localities. Hampstead Heath and the neighbouring woods afford se- 

 veral well-known stations ; it occurs also in Scotland and Wales, and 

 Mr. Mackay observes that it is frequent in Ireland. It is apparently 

 common on the continent of Europe, but does not reach the extreme 

 north, not being mentioned by Linneus or Wahlenberg as inhabiting 

 Lapland or Sweden. 



Although so common a plant, much difference of opinion appears 

 to prevail respecting the degree of moisture required for its nutriment, 

 as will be seen by a reference to the following pages of ' The Phyto- 

 logist;'— 588, 618, 621, 648 and 649. 



The more I investigate the subject, the more do I feel strengthened 

 in my original vievr of the case, confessing, however, that my oppor- 

 tunities of judging are confined to two or three localities, of which I 

 select that at Norwood, recorded by Mr. Ilott (Phytol. 295). The site 

 is the brow of the hill, on the road towards Dulwich, below ' The 

 Woodman ' public-house at Norwood ; the ground is partially waste, 

 having apparently been excavated for brick-earth, and is sufficiently 

 moist for little pools of water to collect in the hollows ; partially, how- 

 ever, it is cultivated, there being now (August, 1843), a fine crop of 

 wheat ready for the sickle. The Equisetum is abundantly mixed with 

 the wheat in every direction as far as I could see, but its growth is not 

 luxuriant, few of its stems attaining half the height of the wheat, and 

 many falling very far short of even that stature. While this fact, how- 

 ever, proves that it will grow in soil sufficiently dry to produce good 

 wheat, its diminished size affords little evidence on either side, for 

 the constant disturbing of the roots in arable land produces an equal- 

 ly diminishing effect on E. arvense, the stems of which in the hedges, 

 where the roots remain untouched, often attain a magnitude four times 

 as great as those in the adjacent fields. On the uncultivated land the 

 most luxuriant growth, measuring four feet and a half or five feet in 

 height, was on the banks where all parts of the plant are comparative- 

 ly free from being disturbed, and the soil loose, loamy and crumbling; 

 but the approach to the little pools, as well as to exposed, dry, and 

 trodden parts, was marked by a gradual decrease in the size of the 

 plants, until, in the immediate vicinity of the water and trodden paths, 

 the stems were perfect pigmies, scarcely four inches in height, thus 

 inducing the conclusion that, in this locality, water is prejudicial, if 

 not fatal, to the existence of the plant, and that closeness an 1 com- 



