50 
HISTORICAL ACCOUNT OF THE HERBARIUM. 
Amongst the interesting plants in the Dalton collection, reference 
may be made to the singular and rare marsh plant Scheuchzevia 
palustvis , L. The honour of adding this rare plant to the British 
flora belongs to the Rev. James Dalton, who discovered it in 
Leckby (or Lakeby) Carr, 1787. 
This remarkable Carr is situate on the west bank of the river 
Swale, and in close proximity to the Asenby gravel pits, Topclifle, 
and Baldersby, North Yorkshire. The Carr is separated from the 
river Swale by a low ridge of hills, composed of gravel, shingle, 
&c., that may have been brought by a glacier in the form of a 
moraine, and thus a hollow or lake may have been formed, which 
probably had a natural drainage into the Swale. 
This lake soon became tenanted by aquatic plants and animals. 
Among other interesting plants of the Carr may be mentioned 
Lysimachia thyrsiflova , L. and Carex limosa, L. The occurrence 
of the Scheuchzevia in Britain has been recorded from Salop, 
Notts, Cheshire, Yorkshire and Perthshire, but in the majority of 
these counties it has become extinct. It is found in the marshes 
and spongy bogs of North and Mid Europe (Arctic), Northern 
Asia and Rocky Mountains, and is named in honour of the two 
Scheuchzers, Swiss botanists. 
This curious plant possesses a long creeping root-stock, which is 
especially adapted to the life and continuance of the species, 
amongst the dense, spongy beds of bog mosses in which it grows. 
When Mr. Dalton visited Lakeby Carr (1787-1827) many of these 
spongy bogs existed, but in 1901 very few remained. 
In this particular Carr, which may be regarded as typical of 
many other Yorkshire carrs, the withdrawal of the water from the 
roots of the plants, and the growth of trees, have hastened the 
extinction of this and similar bog loving species such as Carex 
limosa L., besides many forms of animal life which could not 
survive the altered condition of their surroundings. 
In the herbarium there are some remarkably fine specimens of 
the rare loose-strife Lysimachia thyrsiflova , L., which Mr. Dalton 
collected during his visit to Lakeby Carr (1787-1827). 
The distribution of this plant in Britain is from Lorlar to York¬ 
shire and Nottingham, but its occurrence in these counties is very 
local. It has been observed North of the Alps, and in North 
America : Northern Asia. 
The habitat of the species is in marshes, or by the side of 
ditches. 
