ast, the production of single flowers would
seem to be the result of debilitating causes, connected with the unusual
persistence of the leaves, &c., for while the tree was healthy, double
flowers were produced.

A similar illustration came under the writer's own notice. Some seedling
balsams, of a strain which from long selection and hereditary tendency
produces, year after year, double flowers were, in the spring (of 1866),
allowed to remain in the seed-pans for many weeks after they were ready
to be potted off; they were hence partly starved, and when they bloomed,
they produced single flowers only. But these same plants, when more
liberally treated, produced an abundance of double flowers. Moreover,
other seedlings of the same batch, but sown later, and potted off at the
usual time, produced double flowers as usual. Of a like character is the
fact that the double _Ranunculus asiaticus_ loses its doubleness if the
roots are planted in a poor soil.

On the other hand, the way in which double stocks are stated to be
produced at Erfurt, viz.: by giving the plants a minimum supply of
water, and the other circumstances alluded to as showing the connection
between the production of double flowers, and a deficiency of water, as
well as the experiments of Mr. Monro, go to show that, so far from
plethora, the inducing cause must be more nearly allied to inanition,
though the impoverishing process is, to a certain extent, counteracted
by only allowing a few of the seed-pods to ripen, and thus concentrating
in a small number of flowers the nutriment intended for many.

Professor Edward Morren ('Bull. Acad. Roy. Belg.,' 2me ser., vol. xix,
p. 224) considers the existence of true variegation in leaves, and the
production of double flowers, as antagonistic one to the other; the
former is a sign of weakness, the latter of strength. But it would seem
that the exceptions are so numerous--so many cases of the co-existence
of variegated leaves, and double flowers are known, at least in
individual plants if not in species--that no safe inferences can be
drawn as to this point. Since the above remarks were printed, Professor
Morren has published a second paper on the subject, upholding his former
views as to the incompatibility of variegated foliage (not mere
colouration) and double flowers. In this paper he criticises the
objections raised by the present writer and others, and examines some
of the alleged exceptions. Some of these the