68 Variation 
have clearly confirmed Darwin's ideas. The new evening primroses 
which have sprung in my garden from the old form of Oenothera 
Lamarckiana, and which have evidently been derived from it, in 
each case, by a single mutation, do not differ from their parent 
species in one character only, but in almost all their organs and 
qualities. Oenothera gigas, for example, has stouter stems and denser 
foliage; the leaves are larger and broader; its thick flower-buds 
produce gigantic flowers, but only small fruits with large seeds. 
Correlative changes of this kind are seen in all my new forms, and 
they lend support to the view that in the gradual development of 
highly adapted structures, analogous correlations may have played a 
large part. They easily explain large deviations from an original 
type, without requiring the assumption of too many steps. 
Monstrosities, as their name implies, are widely different in 
character from natural species; they cannot, therefore, be adduced 
as evidence in the investigation of the origin of species. There is 
no doubt that they may have much in common as regards their 
manner of origin, and that the origin of species, once understood, 
may lead to a better understanding of the monstrosities. But the 
reverse is not true, at least not as regards the main lines of develop- 
ment. Here, it is clear, monstrosities cannot have played a part 
of any significance. 
Reversions, or atavistic changes, would seem to give a better 
support to the theory of descent through modifications. These have 
been of paramount importance on many lines of evolution of the 
animal as well as of the vegetable kingdom. It is often assumed 
that monocotyledons are descended from some lower group of 
dicotyledons, probably allied to that which includes the buttercup 
family. On this view the monocotyledons must be assumed to have lost 
the cambium and all its influence on secondary growth, the differentia- 
tion of the flower into calyx and corolla, the second cotyledon or seed- 
leaf and several other characters. Losses of characters such as these 
may have been the result of abrupt changes, but this does not prove 
that the characters themselves have been produced with equal sudden- 
ness. On the contrary, Darwin shows very convincingly that a modi- 
fication may well be developed by a series of steps, and afterwards - 
suddenly disappear. Many monstrosities, such as those represented 
by twisted stems, furnish direct proofs in support of this view, since 
they are produced by the loss of one character and this loss implies 
secondary changes in a large number of other organs and qualities. 
Darwin criticises in detail the hypothesis of great and abrupt 
changes and comes to the conclusion that it does not give even 4 
shadow of an explanation of the origin of species. Itis as improbable 
as it is unnecessary. 
