a cluster of green leaves, as in
the "green roses" occasionally noticed in gardens, and sometimes it
degenerates into a leafy branch. So the botanist regards pistils also as
answering to leaves; that is, to single leaves when simple and separate,
to a whorl of leaves when conjoined.

Sec. 4. MODIFICATIONS OF THE TYPE.

248. =The Deviations=, as they may be called, from the assumed type or
pattern of flower are most various and extensive. The differences
between one species and another of the same genus are comparatively
insignificant; those between different genera are more striking; those
between different families and classes of plants more and more profound.
They represent different adaptations to conditions or modes of life,
some of which have obvious or probable utilities, although others are
beyond particular explanation. The principal modifications may be
conveniently classified. First those which in place of perfect
(otherwise called _hermaphrodite_ or bisexual) flowers, give origin to

249. =Unisexual, or Separated, or Diclinous Flowers=, _imperfect_
flowers, as they have been called in contradistinction to perfect
flowers; but that term is too ambiguous. In these some flowers want the
stamens, while others want the pistils. Taking hermaphrodite flowers as
the pattern, it is natural to say that the missing organs are
_suppressed_. This expression is justified by the very numerous cases in
which the missing parts are _abortive_, that is, are represented by
rudiments or vestiges, which serve to exemplify the plan, although
useless as to office. Unisexual flowers are

_Monoecious_ (or _Monoicous_, i. e. of one household), when flowers of
both sorts or sexes are produced by the same individual plant, as in the
Ricinus or Castor-oil Plant, Fig. 230.

_Dioecious_ (or _Dioicous_, i. e. of separate households), when the
two kinds are borne on different plants; as in Willows, Poplars, Hemp,
and Moonseed, Fig. 231, 232.

_Polygamous_, when the flowers are some of them perfect, and some
staminate or pistillate only.

[Illustration: Fig. 230. Unisexual flowers of Castor-oil plant: _s_,
staminate flower; _p_, pistillate flower.]

[Illustration: Fig. 231, staminate, and 232, pistillate flower of
Moonseed.]

250. A blossom having stamens and no pistil is a _Staminate_ or _Male_
flower. Sometimes it is called a _Sterile_ flower, not appropriately,
for other flowers may equally be sterile. One having pistil but no