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XXXI. 
THE COMPARATIVE RATE OF GROWTH OF A PEDUNCULATED 
AND A SESSILE OAK AT BAYFORDBURY, HERTS. 
By John Hopkinson, F.L.S., F.G.S., Y.P. H. Met. Soc., 
Assoc. Inst. C. E. 
Read at Watford , 12 th April , 1905. 
PLATE VI.* 
John Evelyn, in his ‘ Silva,’ the first book printed by order of 
the Royal Society (folio, 1664), remarks: “ ’T is pity that the 
several kinds of Oak are so rarely known amongst us, that wherever 
they meet with Q,uercus, they take it promiscuously for our common 
Oak, whereas there he many species of that goodly tree, though 
we shall take notice only of the two which are frequent with us. 
These are the Quercus urbana, which grows more upright, and, 
being clean and lighter, is fittest for timber; and the Robur, or 
Quercus silvestris, which, as the name imports, is of a vast robust 
and inflexible nature, of an hard black grain, bearing a smaller 
acorn, and affecting to spread in branches, and to put forth his 
roots more above ground.” 
These trees are generally considered to be distinct species, but 
by some botanists are held to be merely varieties of Quercus Robur. 
Evelyn’s “ silvestris” has its fruit stalked or pedunculate and its 
leaves sessile, and is now usually known as Quercus pedunculata. It 
is our common gnarled and spreading forest oak. His “ urbana ” 
has its fruit sessile or but very shortly stalked and its leaves with 
sholt peduncles, and is now usually known as Quercus sessiliflora. 
It is often seen growing singly. Coleman thus stated its habitat 
in our county : “ Woods, only in those on the highest and most 
heathy ground; the solitary specimens in our parks and pleasure 
grounds are mostly planted; ” and he gave pedunculata as 
“ common ” in “ woods and hedges.” f 
Other points of difference between the two trees are that the 
leaf-buds of sessiliflora are larger and more pointed than those of 
pedunculata , and that its leaves are later to fall. 
Miller, in his ‘ Gardener’s Dictionary,’ made a mistake which 
caused considerable confusion for some time, stating that our 
common English oak was Q. sessiliflora. This mistake was copied 
by Hunter in his edition of Evelyn’s * Silva,’ and it was corrected 
by Martyn in his ‘Flora Rustica’ (1792) and his edition (1807) of 
Miller’s ‘ Dictionary;’ but a mistake once made in two such popular 
works as the ‘ Gardener’s and Botanist’s Dictionary ’ and Hunter’s 
‘ Evelyn ’ does not die easily. 
* The figures on this plate are reproduced from Selby’s ‘ Forest Trees,’ 
pp. 244, 247. 
f ‘ Flora Hertfordiensis,’ pp. 267, 268 ; see also Pryor’s ‘ Flora of Hertford¬ 
shire,’ p. 372, for localities for Q. sessiliflora. 
