[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
Monœcious (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].
Diœcious (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.
Fig. 230. Unisexual flowers of Castor-oil plant: s, staminate flower; p, pistillate flower.
