OP PEOFAGATION BY EYES AND KNAUES. 189 



varying very materially, say several weeks, from 

 each other ; some being ripe or fit for use as early as 

 the middle of May, and others not till 

 June or July. This will be understood 

 by reference to the accompanying 

 sketch. The sets nearest the extremity 

 of the Potato {fig. 17, «) are soonest ripe, 

 and in Lancashire, are planted in warm 

 places in March or the beginning of 

 April, and are ready for the market 

 about the 12th or loth of May. The 

 produce of the next sets (b) is ready in about a fort- 

 night after, and that from the root end (c and d) still 

 later. These roots and sets (from h to d) are usually 

 put together, and the extremity of the root end is 

 thrown aside for the pigs." This fact, if correctly 

 stated, shows, not that the youngest eyes, or those 

 nearest the point of the Potato, are the ripest, which 

 is impossible, but that they -are more excitable, and 

 consequently grow more rapidly than those at the 

 middle or base. 



Besides the cases of propagation by eyes now men- 

 tioned, there is another of which a notice is given by 

 Signer Manetti {Gardener's Magazine, vii. 663), as 

 practised in Italy upon the Olive. It appears that, 

 from old Olive trees, certain knots or excrescences, 

 called uovoli, are cut out of the bark, of which a por- 

 tion is left adhering to them, and being planted, grow 

 into young Olive trees. Of these I have no further 

 account ; but it is evident that the uovoli are no other 

 than our kaaurs, already epokea of (53) under the 



