Of Leaves . 
2 75 
Of leaves. 
T H E leaves of trees or plants are full of innumer¬ 
able ramifications, that convey the perfpirable 
juices to the pores for their difcharge. The fibres of the 
leaf do not Hand in even lines from the ffalk, but always 
in an angular or circular pofture, and their vafcular 
fibres or threads are 3, 5 or 7 ; the reafon of their being 
in this pofition, is for the more ere£t growth and greater 
ftrength of the leaf, as alfo for the fecurity of its fap. 
Another obfervable in the fibres of the leaf, is their or¬ 
derly pofition, fo as to take in an eighth part of a circle, 
as in mallows, in fome a tenth, but in moil a twelfth, 
as in holy-oak, or a fixth, as in fyringa. 
The art of folding up the leaves before their eruption 
out of their germs, &c. is incomparable both for its ele¬ 
gancy and fecurity, viz. in taking up (fo as their forms 
will bear) the leaft room; and in being fo conveniently 
couched, as to be capable of receiving prote&ion from 
the other parts, or of giving it to one another, e gr» firft 
there is the bow-lap, where the leaves are all laid fome- 
what convexly, one over another, but not plaited, but 
Where the leaves are not fo thick fet as to ftand in the 
bow-lap ; there we have the plicature, or the flat lap, as 
in rofe-trees, &c. To thefe Dr. Grew adds their various 
foldings, which he calls by the names of the duplicature, 
multiplicature, the fore rowl, back rowl, and tre rowl 
or treble rowl. 
To thefe curious foldings may be added another noble 
guard by the interpofition of films, &c, of which Dr. Grew 
faith there are about fix ways, viz. leaves, furfoyls, inter- 
foyls, ftaks, heads, and mantlings, 
T 2 
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