547 



rlistiicts iiiusl, however, be always proportioned to the variety of soil, 

 elevation, climate, &c., which the district may possess. Thus a list 

 of plants from a small district of level or swampy ground, would not 

 furnish so much valuable matter as a list from a smaller district where 

 streams or hills produced a difference in the dryness and constitution 

 of the soil. Take for example the neighbourhood of Askern, a small 

 district of Yorkshire, the centre of which is seated in about the mid- 

 dle portion of the great escarpment of magnesian limestone, which 

 runs through the counties of Nottingham, York and Durham. Its ex- 

 tent is about four miles east and west, and two miles north and south. 

 To the east, the magnesian limestone dips under the new red sand- 

 stone, which is covered in this district by an immense swamp. Di- 

 rectly through the district, in a south-easterly direction, runs the river 

 Went, making its way along a picturesque valley, which passes at 

 right angles through the magnesian limestone formation. The river 

 is here about thirty feet above the level of the sea, and the highest 

 hills above its banks are about thi*ee hundred and eighty feet. The 

 villages of Campsall, Burghwallis and Smeaton are seated entirely 

 on the magnesian limestone, whilst Sutton, Askern and Norton in- 

 clude some of the marshy districts lying above the new red sandstone. 



In publishing lists of plants of particular districts, botanists have 

 for a long time felt the inconvenience of going over a number of the 

 names of plants which are common to almost all districts ; and yet, as 

 no rule has been offered which would answer generally for the exclu- 

 sion of common plants, all plants must be included in lists of any value. 



In drawing up a Flora for my ' Account of Askern,' * I have en- 

 deavoured to obviate this difficulty ; and I am not without hope that 

 the idea acted on may be found generally applicable, at least to Great 

 Britain, and that it will lead to the more general publication of local 

 Floras, which will supply material for the perfecting our knowledge 

 of the geographical distribution of plants. 



In the Flora alluded to I have distributed the plants in four tables. 

 In the first table is a numerical statement of the genera and species of 

 each natural order. From this it will be seen that there are 428 spe- 

 cies of phanerogamic plants, belonging to 212 genera and 78 natural 



* An Account of Askern and its Mineral Springs ; together with a Sketch of the 

 Natnral History, and a Brief Topography of the Immediate Neighbourhood. By 

 Edwin Lankester, M.D., F.L.S,, &c. London : Churchill, Princes St., Soho. 1842. 

 A very neat little book, evidently got up with great care on the part of the author, and 

 containing much information relative to the Antiquities, Topography and Natural His- 

 tory of Askern and the surrounding district. — Ed. 



