







346 



DB. F. BUCHANAN WHITE'S 





shoots should be taken. The latter alone are not sufficient, as 

 they often have leaves somewhat different from the normal con- 

 dition ; on the other hand, they are useful for illustrating the 

 stipules. Leaf-specimens should not be taken till the leaves are 

 mature (since the young leaves are deceptive), and, if possible, 

 not earlier than the middle of August. Male catkins should 

 exhibit both unopened and opened anthers. Female catkins 

 should be neither too young nor too old, but be just about the 

 age of fertilization. Specimens in young fruit are also useful. 

 In studying Willows " a practised eye is," as Mr. Leefe says, 



" more to be relied on than the characters found in books ; 



specierum sunt 



i. Ex his modo 



. . . Hinc 



M 











since, as Fries remarks, " Characteres non 



criteria, sed ad species dignoscendas adminicul 



species agnoscuntur, ex vegetationis cognoscuntur 



Linnaeus in speciebus discernendis non characteres sed oculorum 



judiciique aciem laudat." 



Whilst all parts of the plant are variable, some characters, on 

 which a good deal of reliance has been placed, are so inconstant 

 that they may, in many cases at least, be almost or quite ignored, 

 though in other instances they are really of importance. Fami- 

 liarity with the species can alone teach the student what are the 

 points on which he can depend. In many species the presence 

 or absence of stipules, and the shape of these organ?, are of no 

 great value for the discrimination of the plant ; in others it is the 

 very reverse. The presence or absence or the amount of pubes- 

 cence is a character of similar value, as is the presence or absence 

 of glaucosity. 











p 







V. DlSTBIBUTION. 



Though it is probable that the records of distribution in 

 Britain of the true species are, on the whole, correct, the range 

 of the hybrids has yet to be worked out ; and for the sake of 

 accuracy it is perhaps expedient that a new census of the distri- 

 bution of all the British Willows should be taken. 



Perthshire is as rich as — probably richer than — any other county. 

 All the seventeen true species and thirty-one of the hybrids occur 

 in it j and since the neighbouring county of Forfar is probably 

 nearly as productive, and has several hybrids which have not yet 

 been detected in Perthshire, Central Scotland appears to be the 

 metropolis of Willows in Britain. 























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