DEGENERATION OF ORGANS. 
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2nd. Changes are occasioned by a want of vigour in the 
plant to bring all the parts to maturity. Some of the seeds 
thus often fail for want of nourishment; many plants which in 
one flower produce several seeds, often ripen no more than one. 
The horse-chesnut has six seeds, but seldom matures more than 
two ; in the blossom of the oak where six seeds are produced, 
but one acorn is perfected. 
3d. In some cases organs appear from certain changes to be 
incapable of performing their original offices, and thus exhibit 
deformities ; as where a bud is formed, which for want of suffi- 
cient nourishment, or some other cause does not develope itself 
into a leaf, but forms a permanent protuberance or swelling 
upon the stem. The prickly pear exhibits a thick and expanded 
stem, which is formed of leaves imperfectly developed. 
4th. The stamens and pistils through excess of nourishment, 
swell out, and become petals ; all double flowers are formed in 
this manner. The poppy has many stamens, and but four pet- 
als ; but you often see double poppies, with scarcely the vestige 
of a stamen left ; the same change may be observed in the rose, 
which naturally has but five petals and many stamens and pis- 
tils, but in a very full double rose scarcely any appearance of 
either stamen or pistil is to be seen. The stamens more fre- 
quently than the pistils meet with this metamorphosis ; as they 
appear to be more intimately connected with the petals than 
the pistils. 
5th. The petioles or foot stalks often change to leaves. This 
may be seen in an Arabian plant Acacia zilotica, which furnish- 
es the gum arabic. This tree at first exhibits upon one petiole 
six or eight pair of leaves ; this number every year becomes 
less, until all the leaves disappear; the petiole then retaining all 
the nourishment which before was distributed to the leaves, flat- 
tens and expands, and appears in the form of a thick leaf. The 
trees which we call Acacia are not of this genus, but of the 
genus Robinia. 
6th. The peduncles and petioles, sometimes change into ten- 
drils, as in the vine ; this plant at first throws out many large 
leaves and clusters of flowers ; but the food not being sufficient to 
support such a profuse vegetation, the new leaves and clusters 
of flowers appear smaller ; the nourishment becoming still more 
scanty, at length neither flower or leaf is developed, and the 
peduncle and petiole become tendrils, which by attaching them- 
selves to some firm bodies, serve to sustain the rich fruit which 
is perfected on the flower parts of the branch. 
7th. The last change we shall notice is the transformation of 
IV hat changes are occasioned by — How changed. — 
