356 MULTIPLICATION. 



with the primary leaf. But there is no reason at all for 

 supposing the existence of adhesion in these cases ; no 

 trace of any such union is to be seen. A much more 

 natural explanation is that, from some cause or another, 

 development at the apex of the petiole or on the surface 

 of the nerves, instead of taking place in one plane only, 

 as usual, takes place in more than one, thus showing 

 the close relationship, if not the intrinsic identity, 

 between the leaf-stalk and its continuation, the midrib, 

 with the branch and its subdivisions. The form of the 

 leaf-stalk and the arrangement of. the vascular bundles 

 in a circle in the case of the hazel, before alluded to, 

 bear out this notion. Such cases are significant in 

 reference to the notion propounded by M. Casimir de 

 Candolle, that the leaf is the equivalent of a branch in 

 which the upper portion of the vascular circle is 

 abortive.^ 



Compound leaves, as has been stated, occasionally 

 produce an extra number of leaflets ; one of the most 

 famiUar illustrations of this is in the case of the four- 

 leaved shamrock (TrifoUum repens)^ which was gathered 

 at night-time during the full moon by sorceresses, who 

 mixed it with vervain and other ingredients, while 

 young girls in search of a token of perfect happiness 

 made quest of the plant by day. Linn^, who in this 

 matter, at any rate, had less than his usual feeling for 

 romance, says of the four-leaved trefoil that it differs 

 no more from the ordinary trefoil than a man with six 

 fingers differs from one provided with the ordinary 

 number. It should be stated that five and six adven- 

 titious leaflets are found^almost as fi^equently as four. 



Walpers describes a case where the leaf of 1\ repens 

 bore seven leaflets. Schlechtendal alludes to a similar 

 increase in number in Cytisus Labumn/nif and many 

 other instances might be cited. 



For figures or descriptions of four-leaved shamrocks the reader is 

 referred to Lobel, ' Stii-p. Advers.,' Nov., p. 382. TabemeBmontanus 

 'Krauterbuch.' S. 222. Schlechtendal, ' Bot. Zeit.,' ix, p. 583, xiv, p. 71. 



> "Th^rie de la feuille," ' Arch, des Sciences Bibl. Univers..' 1868. 



