371 



and several intermediate spots in which detached plants of each spe- 

 cies or variety, especially of E. Mackaii, occur. I have no doubt 

 whatever that both above and below the part where these stations are, 

 there exist other localities hitherto unrecorded. In no instance have 

 I seen E. hyemale associated with either of the other two, although E. 

 Mackaii grows in its immediate vicinity. In two of the localities E. 

 Mackaii and variegatum grow together, sometimes in juxta-position 

 so close that they seem to spring from the same root. The three grow 

 both upon the banks of the river and in the water, E. hyemale being 

 generally highest and driest, whilst E. variegatum shows most of a 

 tendency to take the water. The former seems to attain its largest 

 growth among loose dry earth, especially where it finds shelter among 

 large stones and trees or bushes, and insinuates its long straggling 

 roots between and under the stones. E. Mackaii appears to prefer a 

 locality where water, oozing from the bank, forms a green moist spot, 

 or finds its way through a rent made by the river, or a channel worn 

 by itself. The water where E. Mackaii thus fixes its habitat, is 

 generally, if not invariably, chalybeate, being accompanied by that 

 orange-coloured mineral or vegetable substance, and exhibiting on its 

 surface that bluish-grey silvery scum, both of which are said to indi- 

 cate the presence of iron. On the brink and in the cavities of such a 

 spot the plant luxuriates freely, and assumes all its different forms, — 

 short, tall and branched. E. variegatum is found in similar situations, 

 generally running farther into the river, and the roots of both plants 

 are frequently stained with the orange- coloured matter just mentioned. 

 E. variegatum manifests a disposition to run its roots under large 

 stones and grow beneath their shelter, where, and in the water, it is 

 most luxuriant. From the stations assigned to it I am inclined to 

 think that its natural habitat is " on the banks and in the bed " of 

 rivers ; and that, when found among sand, it has been carried down 

 by the stream at whose mouth it grows : its greater growth in water 

 seems to favour this conclusion. I think that when E. hyemale and 

 E. Mackaii grow entirely in water, they are much smaller than in their 

 pecuhar situations already described.* 



* Since writing the above I have seen another station for Equisetum Mackaii, and 

 one for E. hyemale, both farther down the river. In these both plants grow more 

 sparingly, — E. hyemale upon a hard, dry, grassy bank, decumbent, almost prostrate, 

 and much more slender than usual ; E. Mackaii in the immediate neighbourhood of 

 mineral water, but growing partly, as it does in some of the other stations, among loose 

 stones in the river's bed, and also nearly prostrate. 



