159, p. 379), for it consists of
two pinnae, each of which bears two pairs of leaflets, of which the inner
basal one is very small. But at the base of each pinna there is a pair of
minute points, evidently rudiments of leaflets, for they are of unequal
sizes, like the two succeeding leaflets. These rudiments are in one sense
embryological, for they exist only during the youth of the leaf, falling
off and disappearing as soon as it is fully grown.
With Desmodium gyrans the two lateral leaflets are very much smaller than
the corresponding leaflets in most of the species in this large genus; they
vary also in position and size; one or both are sometimes absent; and they
do not sleep like the fully-developed leaflets. They may therefore be
considered as almost rudimentary; and in accordance with the general
principles of embryology, they ought to be more constantly and fully
developed on very young than on old plants. But this is not the case, for
they were quite absent on some young seedlings, and did not appear until
from 10 to 20 leaves had been formed.
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