138 
the family to which they belong ; wherein it will be noticed 
that each stamen is affixed>r adherent to the tube of the corolla, 
but immediately in front of a petal, and not between two petals. 
That this idea of the suppression of another whorl of stamens is 
not without foundation, it may be observed that in the flowers 
of a little denizen of damp meadows, Samolus Valerandi, and 
akin to a primrose, has rudimentary stump-like organs which 
stand affixed to the corolla, and .alternate with the petals; 
while the true stamens alternate with the former ; and there- 
fore, as in the Primrose, stand immediately in front of the 
petals. In the Primrose itself, no trace of any such suppressed 
whorl of stamens is ever apparent. In a large number of plants 
which are habitually — normally — without a corolla, the stamens, 
as would be expected, stand in front of, and not alternating 
with, the sepals. . 
27. Although the organs of flowers are usually grouped in 
distinct whorls, yet in many are they spirally arranged ; and 
when this is the case, they can be represented by some fraction 
of the series given for alternate leaves.* 
28. A point now to be particularly observed, is that these 
two arrangements, viz. the ee spiral ” and the (C verticillate (or 
“ whorled,” including the “ opposite ”), appear to be due to 
forces acting independently of each other ; for it is rare to find 
whorls passing into spirals, and still rarer for spirals to pass 
into whorls, — if, indeed, it ever occurs. 
29. The Jerusalem Artichoke, however, furnishes many illus- 
trations of the former process, and in some instances, of the 
latter, though no gradual transition from a spiral to ‘verticillate* 
or opposite conditions ever occurred in the cases examined. 
30. A description of a few examples will be sufficient to 
enable it to be understood how a passage from opposite or ver- 
ticillate leaves into spiral arrangements can be effected. Ex. I. 
The change from the opposite (decussate) leaves into the f 
divergence. This occurred somewhat frequently as follows : A 
pair of leaves slightly converge to one side, the angular distance 
between them being about 150°. The succeeding pair likewise 
converge, but have a somewhat less angle, one of the leaves in 
each case becoming slightly elevated by the development of an 
internode ; so that the sixth leaf now appears over the first, or 
the lowest leaf of the first pair that converged to one side. It 
must be noted that the angles between the radii drawn to the 
position of the converging leaves do not accurately contain 144 , 
* A point worthy of note is, that the free portions of the corolla of a 
primrose overlap one another in just such a way as corresponds to the % ar- 
rangement of spiral leaves ; though, of course, they are actually verticillate. 
