er stage, after
the elongation of the inflorescence, rosettes of leaves are produced
instead of flowers, and structures intermediate between the two kinds of
organs; a number of peculiar plant-forms are thus obtained (Cf. Lotsy,
"Vorlesungen uber Deszendenztheorien", Vol. II. pl. 3, Jena, 1908.)
Abnormalities in the greatest variety are produced in flowers by varying
the time at which the stimulus is applied, and by the cooperation
of other factors such as temperature, darkness, etc. In number and
arrangement the several floral members vary within wide limits;
sepals, petals, stamens, and carpels are altered in form and colour, a
transformation of stamens to carpels and from carpels to stamens occurs
in varying degrees. The majority of the deviations observed had not
previously been seen either under natural conditions or in cultivation;
they were first brought to light through the influence of external
factors.

Such transformations of flowers become apparent at a time, which is
separated by about two months from the period at which the particular
cause began to act. There is, therefore, no close connection between
the appearance of the modifications and the external conditions which
prevail at the moment. When we are ignorant of the causes which are
operative so long before the results are seen, we gain the impression
that such variations as occur are spontaneous or autonomous expressions
of the inner nature of the plant. It is much more likely that, as in
Sempervivum, they were originally produced by an external stimulus which
had previously reached the sexual cells or the young embryo. In any case
abnormalities of this kind appear to be of a special type as compared
with ordinary fluctuating variations. Darwin pointed out this
difference; Bateson (Bateson, "Materials for the study of Variation",
London, 1894, page 5.) has attempted to make the distinction sharper, at
the same time emphasising its importance in heredity.

Bateson applies the term CONTINUOUS to small variations connected with
one another by transitional stages, while those which are more striking
and characterised from the first by a certain completeness, he names
DISCONTINUOUS. He drew attention to a great difficulty which stands in
the way of Lamarck's hypothesis, as also of Darwin's view. "According to
both theories, specific diversity of form is consequent upon diversity
of environment, and diversity of environment is thus the ultimate
measure o