“fF 
SER m Si tr cone ind ! Physiological Bie 
remind one in their form of the three or Fives fabed ey 
- The abortion of leaves does not, however, always lead to a 
the production of spines. In many species of acacia the 5747) 
lamina is so little developed, that often nothing remains — 
but the petiole, which is then called a phyMode; and in 
some species this transformation of the leaf 1s so common 
that it can scarcely be considered as abnormal. — All these 
peculiarities, so far as they are not hereditary, ze trans- 
mitted through the seed, are due to the poverty of the soil. 
As poverty of soil leads to abortion, so an unusual increase 
in development of the axial or foliar organs is usually the 
result.of too powerful nutrition ; either the transmission of 
nutrient substances frem the soil is in itself too abundant, 
or a want of due proportion between the parts above 
and below the surface 1s caused by too vigorous cutting 
away of branches or leaves. ‘The latter course is generally 
pursued by gardeners, who aim at obtaining unusually 
large fruits or flowers by cutting away blossoms, young 
fruits, leafy shoots, &c. Finally, it has already been stated 
that an unusual development of the stem may result from a 
deficiency of light; and this is always the case in the 
etiolated parts of many plants. 
Abnormalities in the number of organs are not un- 
common. In the clover, for example, an increase in the 
number of leaflets of the normally trifoliolate leaf is frequent. 
In the dédoublement or ‘ doubling’ of flowers again, to which 
- more particular reference will be made hereafter, in addition 
to the transformaticn of one of the floral organs into— 
another, as stamens into petals, there 1s generally also a 
-multiplication of the floral whorls ; for example, in ee 
of a single whorl of stamens, two whorls of petals, &c., 
happens in the pink, which has normally only five vetada ag 
and ten stamens, but when double, often twenty or more 
epetals” The change in the relative number of parts is not . 
however, always in the way of increase, but as often, per-* 
haps, of a ee of the number of the organs concerned. ey 
