bud, lengthens and bears the flower-bud on its sides as in a
raceme.

In the hyacinth, the inflorescence of which is properly indefinite, the
terminal flower may frequently be found to expand first, though in order
of development it may have been the last formed.

It occasionally happens that certain plants will, contrary to their
usual custom, bloom twice in the same season; this usually arises from
the premature development of buds which, under ordinary circumstances,
would not unfold till the following spring. In these instances of what
the French term "fleuraison anticipee," the position of inflorescence is
not changed, but there are other cases where the position of the
inflorescence is altered, as in the laburnum, where, in some seasons,
racemes may be seen springing from short lateral "spurs" along the sides
of the branches, as well as from the extremities of long shoots.

Of a similar nature are those cases wherein stems or branches usually
sterile become fertile; this happens in _Equisetaceae_,[187] in
_Restiaceae_, and other orders. In the equisetums, the condition in
question has been specially noticed to occur after prolonged drought.

_Equisetaceae_ are likewise subject to an anomaly called by Duval Jouve
interruption of the spike, and wherein the scales bearing the spore
cases are separated by whorls of branches instead of forming one compact
unbroken spike as usual.

This alternation of the organs of vegetation and reproduction may also
be seen occasionally in _Typha_, and other plants.

Kirschleger describes a case in which the male catkins of _Salix
cinerea_ were placed at the ends of the branches instead of being
lateral productions; moreover the usual articulation was not formed, so
that the catkin was persistent instead of deciduous.[188]

=Supra-soriferous ferns.=--In the great majority of ferns the sori or
clusters of spore cases are placed on the under surface of the fronds;
nevertheless, a few cases are on record where the fructification is
produced on the upper as well as on the lower surface, and sometimes
abundantly so. This occasionally happens from the elongation of the
normally placed sorus, which thus extends to the margin, and returns on
the upper side, when the sori chance to be placed opposite to the
marginal crenatures. But it is also frequently the case that the sori
are produced on the upper side, distinctly within the margin, and where
there are no corresponding sori beneath.