216 
A CENTURY’S CHANGES 
IN THE SHEFFIELD DISTRICT FLORA. 
C. F. INNOCENT. 
RATHER more than a century ago Jonathan Salt formed a 
herbarium, and wrote a catalogue of “ Plants observed to grow 
wild in the neighbourhood of Sheffield,’ of which town he was a 
native and a resident ; the herbarium is now in the Sheffield 
Public Museum, and the Catalogue is in the Library of the 
Sheffield Literary and Philosophical Society. The habitats are 
given for nearly all the plants except those most common, and 
therefore, it seemed desirable to ascertain the changes which 
had occurred in the local flora during the nineteenth century 
as far as was possible from the records. After some years’ 
work I find that of 729 species of local plants in the herbarium 
and the catalogue, 166 species may be looked upon as now 
entirely or almost extinct. 
It is evident that if the conditions of existence in any 
locality remain the same, so also will the local plants; but 
the conditions can remain absolutely the same in theory only, 
so that the continuance of species in a locality is due to their 
ability to survive variation from the so-called * optimal con- 
dition,’ and the greater the range of endurance the greater the 
survival value of the plant. Ihave found that some uncommon 
plants are still growing in the habitats recorded by Salt, such 
as Cardamine impatiens at Matlock on the Derwent bank. 
It has been thought that the flora changes even if the 
conditions remain the same, but they do not so remain; the 
conditions change with every floral new-comer. 
In a marsh, at Aldwark, Rotherham, Salt discovered Carex 
elongata, for the first time in England, and from the same 
marsh he recorded Stellaria glauca, Oenanthe Phellandrium, 
Carex curta. The marsh is still in existence, and at the present 
time grow there :— 
Nasturtium anvphibium. | Ivis pseudacorus. 
Oenanthe Phellandrium. | Carex vulpina. 
Hottonia palustris. -C. acuta. 
Lysimachia nummularia. | C. vesicaria. 
Glyceria fluitans. 
Nasturtium, Lysimachia, and Iris are apparently new- 
comers since Salt’s time, for if not, he would probably have 
recorded them, and if they are new-comers their arrival changed 
the conditions of existence for the older inhabitants. 
But it appears that the decrease in species in the Flora 
of this district is on the whole due to man; his influence is 
both direct and indirect. For the plants may be directly 
exterminated by man himself or they may be destroyed by the 
effects of his activities, such as the extended use of machinery, 
and the repeal of the Corn Laws. 
Naturalist, 
