INTRODUCTION. xxxi 
Lingua, Typha angustifolia, Potamogeton serratus, Ranunculus 
Drouetit, Carex axillaris, C.vesicaria, Habenaria viridis, Lathyrus 
Nissolia, Fritillaria, Mentha cardiaca, Rosa tomentosa, Blysmus, 
Pedicularis palustris, Hottonia, Callitriche obtusangula, Dipsa- 
cus pilosus, Rosa Watsont, Pimpinella major, Anagallis tenella, 
Valeriana dioica, Myriophyllum spicatum, Avena pratensis, 
Vulpia myuros, Catabrosa aquatica, Festuca triflora, Carda- 
mine amara, Stellaria palustris, Bromus racemosus, Polygonum 
mite, 
Other interesting plants of the Cherwell district are Lonicera 
Caprifolium, Myogalum nutans, O. wmbellatum, Narcissus major, 
Helleborus viridis, Lamium hybridum, L.maculatum, L. decipiens, 
Catabrosa, Salix rubra, amygdalina, viminalis, Smithiana, 
purpurea, Nasturtium amphibium, sylvestre, Silene noctiflora, 
Ranunculus sceleratus, Cicuta virosa, Asplenium Adiantum 
nigrum, Trichomanes. 
5. The Isis or Upper Thames district is a large tract 
of country drained by the Thames from its entrance into 
the county to its union with the Cherwell at Oxford, including 
the country drained by its tributaries, the Windrush and Even- 
lode. It is 22 miles long, and 18 broad in its extreme length 
and breadth. Its boundaries are as follows :—In the north- 
west corner, where the counties of Warwick, Worcester, 
Gloucester, and Oxford meet at the Four Shire stones, the district 
is bounded on the north by Warwickshire, and follows the 
county line in a north-easterly direction till it meets with the 
Stour district about Hotley Hill farm. It then turns directly 
south, by Great Rollright to Over Norton Common, when the 
Upper Cherwell or Swere district forms its northern border to 
Dunstew, and also its eastern border to Oxford. Its southern 
limit is the Thames from Oxford to Kelmscott, Berkshire being 
separated from it by that river. Its western border is Glouces- 
tershire from Kelmscott northwards to the Four Shire stones. 
The Thames enters Oxford, as it has been said, at Kelmscott, 
passing through flat and not very interesting country, to the 
ancient bridge of Radcot, and through broad alluvial meadows, 
by Bampton with its spire, a prominent object in the landscape; 
and on through ‘low meadows often overflown by rage of rain,’ 
as Leland says, in which the Charney brook assists, by adding 
