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POPULAR SCIENCE REVIEW. 
with this the column or style of the pistil elongates, and in its 
upward progress effectually sweeps off the liberated pollen (a 1 ), 
and thus the office of fertilization is brought about. 
- Figs. 2 and 3 are illustrations of a monstrous change in 
these simple arrangements. In these the petals have increased 
beyond the normal number of five, to ten ; they are not united 
into a tube by their claws, but are separate and distinct. Of 
these, half are distinct petals, as fig. 4 ; and alternating with 
these, and forming an inner whorl, will be found stameniferous 
petals, as fig. 3a, and figs. 5 and 6. 
In some examples of these monstrous flowers, enlarged 
stamens may be seen, as fig. 7 ; in which case the pistil is found 
usually more or less perfect, and the petals not wholly, but only 
partially free : here fertilization is possible, but there can be 
but little doubt that the resulting seed, on cultivation, would 
bring about the more complete change of form as represented 
in figs. 2 and 3. In this latter the pistil is abortive, consisting 
only of a small point representative of the style, and of course 
the seeds are not developed. 
Illustrations of the above may be found in what is called the 
Double Periwinkle planted on most rockeries, and about the 
“ wilderness,” especially of our older gardens ; and they may 
be viewed by the tyro in botany as objects of great interest, 
illustrating the fact that what was once called a monopetalous 
corolla is after all composed of five petals united at then' base 
by cementation, whilst here the stamens may be viewed as 
metamorphosed petals. 
EXPLANATION OF PLATE XX. 
Pig. 1. An opened flower of Vinca minor showing the pistil just before it 
pushes through the stamens by elongation. 
Pig. la. Pollen of ditto, 300 diameters. 
Pigs. 2 & 3. Metamorphosed flowers, each with ten distinct petals. 
Fig. 4. A separated petal. 
Figs. 5 & 6. Petaloid Stamens. 
Fig. 7. A true stamen. 
