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 
familiar illustrations of this is in the case of the four- 
leaved shamrock (Trifoliwm 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. Linné, who im 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 frequently as four. 
Walpers describes a case where the leaf of 7. repens 
bore seven leaflets. Schlechtendal alludes to a similar 
increase in number in Cytisus Laburnwm, and many 
other instances might be cited. 
For figures or descriptions of four-leaved shamrocks the reader is 
referred to Lobel, ‘Stirp. Advers., Nov., p. 382. Taberneemontanus 
‘Krauterbuch,’ §, 222. Schlechtendal, ‘ Bot. Zeit.,’ ix, p, 083, xiv, p. a. 
1 “Théorie de la feuille,”’ ‘ Av ch. des Aono Bibl. Tae rs 1868, 

