they did not in the least flag, could seldom
be fertilised; this occurred even with potted {165} plants if the roots
had grown out of the hole at the bottom. In some few cases, however, as
with Digitalis, transplantation did not prevent fertilisation; and
according to the testimony of Mawz, _Brassica rapa_, when pulled up by
its roots and placed in water, ripened its seed. Flower-stems of
several monocotyledonous plants when cut off and placed in water
likewise produce seed. But in these cases I presume that the flowers
had been already fertilised, for Herbert[405] found with the Crocus
that the plants might be removed or mutilated after the act of
fertilisation, and would still perfect their seeds; but that, if
transplanted before being fertilised, the application of pollen was
powerless.

Plants which have been long cultivated can generally endure with
undiminished fertility various and great changes; but not in most cases
so great a change of climate as domesticated animals. It is remarkable
that many plants under these circumstances are so much affected that
the proportions and the nature of their chemical ingredients are
modified, yet their fertility is unimpaired. Thus, as Dr. Falconer
informs me, there is a great difference in the character of the fibre
in hemp, in the quantity of oil in the seed of the Linum, in the
proportion of narcotin to morphine in the poppy, in gluten to starch in
wheat, when these plants are cultivated on the plains and on the
mountains of India; nevertheless, they all remain fully fertile.

_Contabescence._--Gaertner has designated by this term a peculiar
condition of the anthers in certain plants, in which they are
shrivelled, or become brown and tough, and contain no good pollen. When
in this state they exactly resemble the anthers of the most sterile
hybrids. Gaertner,[406] in his discussion on this subject, has shown
that plants of many orders are occasionally thus affected; but the
Caryophyllaceae and Liliaceae suffer most, and to these orders, I
think, the Ericaceae may be added. Contabescence varies in degree, but
on the same plant all the flowers are generally affected to nearly the
same extent. The anthers are affected at a very early period in the
flower-bud, and remain in the same state (with one recorded exception)
during the life of the