stage of organization. And since the adaptive variation is quickly
perfected as compared with automatic evolution, although extremely
slowly as compared with the duration of the ontogeny, an organization
may change its adaptation several times while it remains at the same
grade of organization and division of labor. Since there are also
numerous different kinds of adaptation, a phyletic line may divide at
each point into several adaptive forms, which appear in the taxonomic
system as species, genera, often even as whole families, while in other
cases various degrees of organization have appeared in one family.

20. LAWS OF EVOLUTION OF THE PLANT KINGDOM.

In the sub-organic kingdom, which precedes the plant and animal
kingdoms, (see page 5), there are gradually formed from the
spontaneously generated plasma independent cells with their
characteristic properties, _i.e._, growth by intussusception of micellae,
formation of a plasmic cuticle, and a non-plasmic membrane about the
same, division of the cells, separation of the cells thus formed, and
free cell formation within the cell contents. These properties are
inherited from the sub-organic kingdom by the plants and animals which
follow in the next stage of phylogeny. The evolution of the plant
kingdom proceeds through the following regular processes, which continue
to operate through the entire phylogenetic series.

_Law of Phylogenetic Combination._--The simplest of all plants are cells
of round form, which grow and reproduce themselves by division, budding
or free cell formation. From the fact that the younger generation of
cells, instead of separating from each other and growing to independent
plant individuals, remain united with each other, multicellular plants
arise from unicellular. The same transformation of the reproductive
cells into non-separable tissue cells is repeated several times in
multicellular plants and serves to enlarge the individual. There is
manifested in this phylogenetic process the tendency of the plant to
combine in the higher stages into one complex whole those parts which in
the lower stages tend to be independent. A similar unifying tendency is
revealed also in those plant members which have arisen by
differentiation and represent a system only by their being connected at
certain points. These combine in the higher stages and form ultimately
continuous tissues.

_Law of Phylogenetic Complication or Ampliation, Differentiation and
R