78 0)1 the Origin and Distribution of the British Flora. 



require a scientific division of the country into provinces. 

 This I have attempted, so far as England is concerned, in a 

 paper recently published by the Geologists' Association.^^ 

 "We could hardly have a better guide to critical botany than 

 Professor Babington's ' Manual ' ; and for the systematic 

 examination of the plants of our county we are fortunate in 

 possessing Mr. Gibson's ' Flora of Essex.' In the ai^pendices 

 to this work Mr. Gibson compares the Essex list with those 

 of plants found in the adjacent counties ; and similar tables 

 are given for Middlesex in Messrs. Trimen and Dyer's Flora 

 of that county. Unfortunately the subdivisions adopted by 

 Mr. Gibson are not the natural lines of watershed dividing 

 the river basins. These undoubtedly afford the most scientific 

 boundary lines, and in the botanical map of England in my 

 paper, to which I have just alluded, Essex falls partly into 

 three provinces — (1) the basin of the Thames and the South- 

 East, including in this county the valleys of the Lea, the 

 Boding, and the Marditch ; (2) East Anglia, to which 

 belong the valley of the Black water, in which we now are, 

 that of the Colne and the Stour, and that of the Crouch; 

 and (8) a small district near Saffron Walden drained by the 

 great Ouse. Whilst I should not be sorry if our Club were 

 the means of adding to the four British species peculiar to 

 Essex, I should be still more glad to hear of the rediscovery 

 of any of those plants which Mr. Gibson enumerates as lost, 

 and shall be fully satisfied if my remarks are the means of 

 directing the attention of a small number to the geographical 

 relations of our plants. ^*^ 



s'J " On the Geological and other causes that affect the Distribution of 

 the British Flora," Proc. Geol. Assoc, vol. vi., No. 9. 



80 Among the authorities to which I have been specially indebted are 

 Mr. J. G. Baker's ' Botanical Geography ' (1875) ; Mr. Bentham's Presi- 

 dential Address for 1869; Professor Morris's article, "The Cretaceous 

 Flora" (1876) ; Professor Lesquereux's work with the same title (1874); 

 Mr. Wallace's ' Island Life ' (1880) ; the various works of Professor Heer, 

 and of Mr. Watson ; Professor Forbes's essay ; Profossor Dyer's article 

 "Distribution" in the 'Encyclopedia Britannica' (1877) ; and Professor 

 Henslow's paper, with the same title as the present one, in the Watford 

 Society's Transactions for 1879. I have not yet seen Count Saporta's 



