crossed parentage, has been described in France,[120] which bears fruit
with one half larger than the other, of a red colour, acid taste, and
peculiar odour; the other side being greenish-yellow and very sweet: it
is said scarcely ever to include perfectly developed seed. I suppose
that this is not the same tree as that which Gaudichaud[121] exhibited
before the French institute, bearing on the same branch two distinct
kinds of apples, one a _reinette rouge,_ and the other like a _reinette
canada jaunâtre_: this double-bearing variety can be propagated by
grafts, and continues to produce both kinds; its origin is unknown. The
Rev. J. D. La Touche sent me a coloured drawing of an apple which he
brought from Canada, of which half, surrounding and including the whole
of the calyx and the insertion of the foot-stalk, is green, the other
half being brown and of the nature of the _pomme gris_ apple, with the
line of separation between the two halves exactly defined. The tree was
a grafted one, and Mr. La Touche thinks that the branches which bore
this curious apple sprung from the point of junction of the graft and
stock: had this fact been ascertained, the case would probably have
come into the class of graft-hybrids already given. But the branch may
have sprung from the stock, which no doubt was a seedling.
Prof. H. Lecoq, who has made a great number of crossings between the
differently coloured varieties of _Mirabilis jalapa,_[122] finds that
in the seedlings the colours rarely combine, but form distinct stripes;
or half the flower is of one colour and half of a different colour.
Some varieties regularly bear flowers striped with yellow, white, and
red; but plants of such varieties occasionally produce on the same root
branches with uniformly coloured flowers of all three tints, and other
branches with half-and-half coloured flowers, and others with marbled
flowers. Gallesio[123] crossed reciprocally white and red carnations,
and the seedlings were striped; but some of the striped plants also
bore entirely white and entirely red flowers. Some of these plants
produced one year red flowers alone, and in the following year striped
flowers; or conversely, some plants, after having borne for two or
three years striped flowers, would revert and bear exclusively red
flowers. It may be worth mentioning that I fertilised the _Purple
Sweet-pea (Lathyrus odoratus)_ with pollen from the light-coloured
_Painted Lady_: seedlings raised from the same pod were not
intermediate in character, but perfectly resembled either parent. Later
in the summer, the plants which had at first borne flowers identical
with those of the _Painted Lady,_ produced flowers streaked and
blotched with purple; showing in these darker marks a tendency to
reversion to the mother-variety. Andrew Knight[124] fertilised two
white grapes with pollen of the Aleppo grape, which is darkly
variegated both in its leaves and fruit. The result was that the young
seedlings were not at first variegated, but all became variegated
during the succeeding summer; besides this, many produced on the same
plant bunches of grapes which were all black, or all white, or
lead-coloured striped with white, or white dotted with minute black
stripes; and grapes of all these shades could frequently be found on
the same foot-stalk.
I will append a very curious case, not of bud-variation, but of two
cohering embryos, different in character and contained within the same
seed. A distinguished botanist, Mr. G. H. Thwaites,[125] states that a
seed from _Fuchsia coccinea_ fertilised by _F. fulgens,_ contained two
embryos, and was “a true vegetable twin.” The two plants produced from
the two embryos were “extremely different in appearance and character,”
though both resembled other hybrids of the same parentage produced at
the same time. These twin plants “were closely coherent, below the two
pairs of cotyledon-leaves, into a single cylindrical stem, so that they
had subsequently the appearance of being branches on one trunk.” Had
the two united stems grown up to their full height, instead of dying, a
curiously mixed hybrid would have been produced. A mongrel melon
described by Sageret[126] may perhaps have thus originated; for the two
main branches, which arose from two cotyledon-buds, produced very
different fruit,—on the one branch like that of the paternal variety,
and on the other branch like to a certain extent that of the maternal
variety, the melon of China.
In most of these cases of crossed varieties, and in some of the cases
of crossed species, the colours proper to both parents appeared in the
seedlings, as soon as they first flowered, in the form of stripes or
larger segments, or as whole flowers or fruit of different kinds borne
on the same plant; and in this case the appearance of the two colours
cannot strictly be said to be due to reversion, but to some incapacity
of fusion. When, however, the later flowers or fruit produced during
the same season, or during a succeeding year or generation, become
striped or half-and-half, etc., the segregation of the two colours is
strictly a case of reversion by bud-variation. Whether all the many
recorded cases of striped flowers and fruit are due to previous
hybridisation and reversion is by no means clear, for instance with
peaches and nectarines, moss-roses, etc. In a future chapter I shall
show that, with animals of crossed parentage, the same individual has
been known to change its character during growth, and to revert to one
of its parents which it did not at first resemble. Finally, from the
various facts now given, there can be no doubt that the same individual
plant, whether a hybrid or a mongrel, sometimes returns in its leaves,
flowers, and fruit, either wholly or by segments, to both parent-forms.
_On the direct or immediate action of the male element on the mother
form._—Another remarkable class of facts must be here considered,
firstly, because they have a high physiological importance, and
secondly, because they have been supposed to account for some cases of
bud-variation. I refer to the direct action of the male element, not in
the ordinary way on the ovules, but on certain parts of the female
plant, or in case of animals on the subsequent progeny of the female by
a second male. I may premise that with plants the ovarium and the coats
of the ovules are obviously parts of the female, and it could not have
been anticipated that they would have been affected by the pollen of a
foreign variety or species, although the development of the embryo,
inside the embryonic sack, inside the ovule and ovarium, of course,
depends on the male element.
Even as long ago as 1729 it was observed[127] that white and blue
varieties of the Pea, when planted near each other, mutually crossed,
no doubt through the agency of bees, and in the autumn blue and white
peas were found within the same pods. Wiegmann made an exactly similar
observation in the present century. The same result has followed
several times when a variety with peas of one colour has been
artificially crossed by a differently-coloured variety.[128] These
statements led Gärtner, who was highly sceptical on the subject,
carefully to try a long series of experiments: he selected the most
constant varieties, and the result conclusively showed that the colour
of the skin of the pea is modified when pollen of a differently
coloured variety is used. This conclusion has since been confirmed by
experiments made by the Rev. J. M. Berkeley.[129]
Mr. Laxton of Stamford, whilst making experiments on peas for the
express purpose of ascertaining the influence of foreign pollen on the
mother-plant, has recently[130] observed an important additional fact.
He fertilised the Tall Sugar-pea, which bears very thin green pods,
becoming brownish-white when dry, with pollen of the Purple-podded pea,
which, as its name expresses, has dark-purple pods with very thick
skin, becoming pale reddish purple when dry. Mr. Laxton has cultivated
the tall sugar-pea during twenty years, and has never seen or heard of
it producing a purple pod: nevertheless, a flower fertilised by pollen
from the purple-pod yielded a pod clouded with purplish-red which Mr.
Laxton kindly gave to me. A space of about two inches in length towards
the extremity of the pod, and a smaller space near the stalk, were thus
coloured. On comparing the colour with that of the purple pod, both
pods having been first dried and then soaked in water, it was found to
be identically the same; and in both the colour was confined to the
cells lying immediately beneath the outer skin of the pod. The valves
of the crossed pod were also decidedly thicker and stronger than those
of the pods of the mother-plant, but this may possibly have been an
accidental circumstance, for I know not how far their thickness is a
variable character in the Tall Sugar-pea.
The peas of the Tall Sugar-pea, when dry, are pale greenish-brown,
thickly covered with dots of dark purple so minute as to be visible
only through a lens, and Mr. Laxton has never seen or heard of this
variety producing a purple pea; but in the crossed pod one of the peas
was of a uniform beautiful violet-purple tint, and a second was
irregularly clouded with pale purple. The colour lies in the outer of
the two coats which surround the pea. As the peas of the purple-podded
variety when dry are of a pale greenish-buff, it would at first appear
that this remarkable change of colour in the peas in the crossed pod
could not have been caused by the direct action of the pollen of the
purple-pod: but when we bear in mind that this latter variety has
purple flowers, purple marks on its stipules, and purple pods; and that
the Tall Sugar-pea likewise has purple flowers and stipules, and
microscopically minute purple dots on the peas, we can hardly doubt
that the tendency to the production of purple in both parents has in
combination modified the colour of the peas in the crossed pod. After
having examined these specimens, I crossed the same two varieties, and
the peas in one pod but not the pods themselves, were clouded and
tinted with purplish-red in a much more conspicuous manner than the
peas in the uncrossed pods produced at the same time by the same
plants. I may notice as a caution that Mr. Laxton sent me various other
crossed peas slightly, or even greatly, modified in colour; but the
change in these cases was due, as had been suspected by Mr. Laxton, to
the altered colour of the cotyledons, seen through the transparent
coats of the peas; and as the cotyledons are parts of the embryo, these
cases are not in any way remarkable.
Turning now to the genus Matthiola. The pollen of one kind of stock
sometimes affects the colour of the seeds of another kind, used as the
mother-plant. I give the following case the more readily, as Gärtner
doubted similar statements previously made with respect to the stock by
other observers. A well-known horticulturist, Major Trevor Clarke,
informs me[131] that the seeds of the large red-flowered _biennial_
stock, _Matthiola annua_ (_Cocardeau_ of the French), are light brown,
and those of the purple branching Queen stock (_M. incana_) are
violet-black; and he found that, when flowers of the red stock were
fertilised by pollen from the purple stock, they yielded about fifty
per cent of _black_ seeds. He sent me four pods from a red flowered
plant, two of which had been fertilised by their own pollen, and they
included pale brown seed; and two which had been crossed by pollen from
the purple kind, and they included seeds all deeply tinged with black.
These latter seeds yielded purple-flowered plants like their father;
whilst the pale brown seeds yielded normal red-flowered plants; and
Major Clarke, by sowing similar seeds, has observed on a greater scale
the same result. The evidence in this case of the direct action of the
pollen of one species on the colour of the seeds of another species
appears to me conclusive.
Gallesio[132] fertilised the flowers of an orange with pollen from the
lemon; and one fruit thus produced bore a longitudinal stripe of peel
having the colour, flavour, and other characters of the lemon. Mr.
Anderson[133] fertilised a green-fleshed melon with pollen from a
scarlet-fleshed kind; in two of the fruits “a sensible change was
perceptible: and four other fruits were somewhat altered both
internally and externally.” The seeds of the two first-mentioned fruits
produced plants partaking of the good properties of both parents. In
the United States, where Cucurbitaceæ are largely cultivated, it is the
popular belief[134] that the fruit is thus directly affected hy foreign
pollen; and I have received a similar statement with respect to the
cucumber in England. It is believed that grapes have been thus affected
in colour, size, and shape: in France a pale-coloured grape had its
juice tinted by the pollen of the dark-coloured Teinturier; in Germany
a variety bore berries which were affected by the pollen of two
adjoining kinds; some of the berries being only partially affected or
mottled.[135]
As long ago as 1751[136] it was observed that, when
differently-coloured varieties of maize grew near each other, they
mutually affected each other’s seeds, and this is now a popular belief
in the United States. Dr. Savi[137] tried the experiment with care: he
sowed yellow and black-seeded maize together, and on the same ear some
of the seeds were yellow, some black, and some mottled, the differently
coloured seeds being arranged irregularly or in rows. Prof. Hildebrand
has repeated the experiment[138] with the precaution of ascertaining
that the mother-plant was true. A kind bearing yellow grains was
fertilised with pollen of a kind having brown grains, and two ears
produced yellow grains mingled with others of a dirty violet tint. A
third ear had only yellow grains, but one side of the spindle was
tinted of a reddish-brown; so that here we have the important fact of
the influence of the foreign pollen extending to the axis. Mr. Arnold,
in Canada, varied the experiment in an interesting manner: “a female
flower was subjected first to the action of pollen from a yellow
variety, and then to that from a white variety; the result was an ear,
each grain of which was yellow below and white above.”[139] With other
plants it has occasionally been observed that the crossed offspring
showed the influence of two kinds of pollen, but in this case the two
kinds affected the mother-plant.
Mr. Sabine states[140] that he has seen the form of the nearly globular
seed-capsule of _Amaryllis vittata_ altered by the application of the
pollen of another species, of which the capsule has gibbous angles.
With an allied genus, a well-known botanist, Maximowicz, has described
in detail the striking results of reciprocally fertilising _Lilium
bulbiferum_ and _ davuricum_ with each other’s pollen. Each species
produced fruit not like its own, but almost identical with that of the
pollen-bearing species; but from an accident only the fruit of the
latter species was carefully examined; the seeds were intermediate in
the development of their wings.[141]
Fritz Müller fertilised _Cattleya leopoldi_ with pollen of _Epidendron
cinnabarinum_; and the capsules contained very few seeds; but these
presented a most wonderful appearance, which, from the description
given, two botanists, Hildebrand and Maximowicz, attribute to the
direct action of the pollen of the Epidendron.[142]
Mr. J. Anderson Henry[143] crossed _Rhododendron dalhousiæ_ with the
pollen of _R. nuttallii,_ which is one of the largest-flowered and
noblest species of the genus. The largest pod produced by the former
species, when fertilised with its own pollen, measured 1¼ inch in
length and 1½ in girth; whilst three of the pods which had been
fertilised by pollen of _R. nuttallii_ measured 1-5/8 inch in length
and no less than 2 inches in girth. Here the effect of the foreign
pollen was apparently confined to increasing the size of the ovarium;
but we must be cautious in assuming, as the following case shows, that
size had been transferred from the male parent to the capsule of the
female plant. Mr. Henry fertilised _Arabis blepharophylla_ with pollen
of _A. soyeri,_ and the pods thus produced, of which he was so kind as
to send me detailed measurements and sketches, were much larger in all
their dimensions than those naturally produced by either the male or
female parent-species. In a future chapter we shall see that the organs
of vegetation in hybrid plants, independently of the character of
either parent, are sometimes developed to a monstrous size; and the
increased size of the pods in the foregoing cases may be an analogous
fact. On the other hand, M. de Saporta informs me that an isolated
female plant of _Pistacia vera_ is very apt to be fertilised by the
pollen of neighbouring plants of _P. terebinthus,_ and in this case the
fruits are only half their proper size, which he attributes to the
influence of the pollen of _P. terebinthus._
No case of the direct action of the pollen of one variety on another is
better authenticated or more remarkable than that of the common apple.
The fruit here consists of the lower part of the calyx and of the upper
part of the flower-peduncle[144] in a metamorphosed condition, so that
the effect of the foreign pollen has extended even beyond the limits of
the ovarium. Cases of apples thus affected were recorded by Bradley in
the early part of the last century; and other cases are given in old
volumes of the ‘Philosophical Transactions’;[145] in one of these a
Russeting apple and an adjoining kind mutually affected each other’s
fruit; and in another case a smooth apple affected a rough-coated kind.
Another instance has been given[146] of two very different apple-trees
growing close to each other, which bore fruit resembling each other,
but only on the adjoining branches. It is, however, almost superfluous
to adduce these or other cases, after that of the St. Valery apple, the
flowers which, from the abortion of the stamens, do not produce pollen,
but are fertilised by the girls of the neighbourhood with pollen of
many kinds; and they bear fruit, “differing from one another in size,
flavour, and colour, but resembling in character the hermaphrodite
kinds by which they have been fertilised.”[147]
I have now shown, on the authority of several excellent observers, in
the case of plants belonging to widely different orders, that the
pollen of one species or variety, when applied to the female of a
distinct form, occasionally causes the coats of the seeds, the ovarium
or fruit, including even the calyx and upper part of the peduncle of
the apple, and the axis of the ear in maize, to be modified. Sometimes
the whole ovarium or all the seeds are thus affected; sometimes only a
certain number of the seeds, as in the case of the pea, or only a part
of the ovarium, as with the striped orange, mottled grapes, and maize,
is thus affected. It must not be supposed that any direct or immediate
effect invariably follows the use of foreign pollen: this is far from
being the case; nor is it known on what conditions the result depends.
Mr. Knight[148] expressly states that he has never seen the fruit thus
affected, though he crossed thousands of apple and other fruit-trees.
There is not the least reason to believe that a branch which has borne
seed or fruit directly modified by foreign pollen is itself affected,
so as afterwards to produce modified buds; such an occurrence, from the
temporary connection of the flower with the stem, would be hardly
possible. Hence, but very few, if any, of the cases of bud-variation in
the fruit of trees, given in the early part of this chapter can be
accounted for by the action of foreign pollen; for such fruits have
commonly been propagated by budding or grafting. It is also obvious
that changes of colour in flowers, which necessarily supervene long
before they are ready for fertilisation, and changes in the shape or
colour of leaves, when due to the appearance of modified buds, can have
no relation to the action of foreign pollen.
The proofs of the action of foreign pollen on the mother-plant have
been given in considerable detail, because this action, as we shall see
in a future chapter, is of the highest theoretical importance, and
because it is in itself a remarkable and apparently anomalous
circumstance. That it is remarkable under a physiological point of view
is clear, for the male element not only affects, in accordance with its
proper function, the germ, but at the same time various parts of the
mother-plant, in the same manner, as it affects the same part in the
seminal offspring from the same two parents. We thus learn that an
ovule is not indispensable for the reception of the influence of the
male element. But this direct action of the male element is not so
anomalous as it at first appears, for it comes into play in the
ordinary fertilisation of many flowers. Gärtner gradually increased the
number of pollen grains until he succeeded in fertilising a Malva, and
has[149] proved that many grains are first expended in the development,
or, as he expresses it, in the satiation, of the pistil and ovarium.
Again, when one plant is fertilised by a widely distinct species, it
often happens that the ovarium is fully and quickly developed without
any seeds being formed; or the coats of the seeds are formed without
any embryo being developed within. Prof. Hildebrand, also, has lately
shown[150] that, in the normal fertilisation of several Orchideæ, the
action of the plant’s own pollen is necessary for the development of
the ovarium; and that this development takes place not only long before
the pollen-tubes have reached the ovules, but even before the placentæ
and ovules have been formed; so that with these orchids the pollen acts
directly on the ovarium. On the other hand, we must not overrate the
efficacy of pollen in the case of hybridised plants, for an embryo may
be formed and its influence excite the surrounding tissues of the
mother-plant, and then perish at a very early age and be thus
overlooked. Again, it is well known that with many plants the ovarium
may be fully developed, though pollen be wholly excluded. Lastly, Mr.
Smith, the late Curator at Kew (as I hear through Dr. Hooker), observed
with an orchid, the _Bonatea speciosa,_ the singular fact that the
development of the ovarium could be effected by the mechanical
irritation of the stigma. Nevertheless, from the number of the
pollen-grains expended “in the satiation of the ovarium and
pistil,”—from the generality of the formation of the ovarium and
seed-coats in hybridised plants which produce no seeds,—and from Dr.
Hildebrand’s observations on orchids, we may admit that in most cases
the swelling of the ovarium, and the formation of the seed-coats are at
least aided, if not wholly caused, by the direct action of the pollen,
independently of the intervention of the fertilised germ. Therefore, in
the previously given cases we have only to believe in the further power
of pollen, when applied to a distinct species or variety, to influence
the shape, size, colour, texture, etc., of certain parts of the
mother-plant.
Turning now to the animal kingdom. If we could imagine the same flower
to yield seeds during successive years, then it would not be very
surprising that a flower of which the ovarium had been modified by
foreign pollen should next year produce, when self-fertilised,
offspring modified by the previous male influence. Closely analogous
cases have actually occurred with animals. In the case often quoted
from Lord Morton,[151] a nearly purely-bred Arabian chestnut mare bore
a hybrid to a quagga; she was subsequently sent to Sir Gore Ouseley,
and produced two colts by a black Arabian horse. These colts were
partially dun-coloured, and were striped on the legs more plainly than
the real hybrid, or even than the quagga. One of the two colts had its
neck and some other parts of its body plainly marked with stripes.
Stripes on the body, not to mention those on the legs, are extremely
rare,—I speak after having long attended to the subject,—with horses of
all kinds in Europe, and are almost unknown in the case of Arabians.
But what makes the case still more striking is that in these colts the
hair of the mane resembled that of the quagga, being short, stiff, and
upright. Hence there can be no doubt that the quagga affected the
character of the offspring subsequently begot by the black Arabian
horse. Mr. Jenner Weir informs me of a strictly parallel case: his
neighbour Mr. Lethbridge, of Blackheath, has a horse, bred by Lord
Mostyn, which had previously borne a foal by a quagga. This horse is
dun with a dark stripe down the back, faint stripes on the forehead
between the eyes, plain stripes on the inner side of the fore-legs and
rather more faint ones on the hind-legs, with no shoulder-stripe. The
mane grows much lower on the forehead than in the horse, but not so low
as in the quagga or zebra. The hoofs are proportionally longer than in
the horse,—so much so that the farrier who first shod this animal, and
knew nothing of its origin, said, “Had I not seen I was shoeing a
horse, I should have thought I was shoeing a donkey.”
With respect to the varieties of our domesticated animals, many similar
and well-authenticated facts have been published,[152] and others have
been communicated to me, plainly showing the influence of the first
male on the progeny subsequently borne by the mother to other males. It
will suffice to give a single instance, recorded in the ‘Philosophical
Transactions,’ in a paper following that by Lord Morton: Mr. Giles put
a sow of Lord Western’s black and white Essex breed to a wild boar of a
deep chestnut colour; and the “pigs produced partook in appearance of
both boar and sow, but in some the chestnut colour of the boar strongly
prevailed.” After the boar had long been dead, the sow was put to a
boar of her own black and white breed—a kind which is well known to
breed very true and never to show any chestnut colour,—yet from this
union the sow produced some young pigs which were plainly marked with
the same chestnut tint as in the first litter. Similar cases have so
frequently occurred, that careful breeders avoid putting a choice
female of any animal to an inferior male, on account of the injury to
her subsequent progeny which may be expected to follow.
Some physiologists have attempted to account for these remarkable
results from a previous impregnation, by the imagination of the mother
having been strongly affected; but it will hereafter be seen that there
are very slight grounds for any such belief. Other physiologists
attribute the result to the close attachment and freely
intercommunicating blood-vessels between the modified embryo and
mother. But the analogy from the action of foreign pollen on the
ovarium, seed-coats, and other parts of the mother-plant, strongly
supports the belief that with animals the male element acts directly on
the female, and not through the crossed embryo. With birds there is no
close connection between the embryo and mother; yet a careful observer,
Dr. Chapuis, states[153] that with pigeons the influence of a first
male sometimes makes itself perceived in the succeeding broods; but
this statement requires confirmation.
_Conclusion and Summary of the Chapter._—The facts given in the latter
half of this chapter are well worthy of consideration, as they show us
in how many extraordinary modes the union of one form with another may
lead to the modification of the seminal offspring or of the buds,
afterwards produced.
There is nothing surprising in the offspring of species or varieties
crossed in the ordinary manner being modified; but the case of two
plants within the same seed, which cohere and differ from each other,
is curious. When a bud is formed after the cellular tissue of two
species or two varieties have been united, and it partakes of the
characters of both parents, the case is wonderful. But I need not here
repeat what has been so lately said on this subject. We have also seen
that in the case of plants the male element may affect in a direct
manner the tissues of the mother, and with animals may lead to the
modification of her future progeny. In the vegetable kingdom the
offspring from a cross between two species or varieties, whether
effected by seminal generation or by grafting, often revert, to a
greater or less degree, in the first or in a succeeding generation, to
the two parent-forms; and this reversion may affect the whole flower,
fruit, or leaf-bud, or only the half or a smaller segment of a single
organ. In some cases, however, such segregation of character apparently
depends on an incapacity for union rather than on reversion, for the
flowers or fruit which are first produced display by segments the
characters of both parents. The various facts here given ought to be
well considered by any one who wishes to embrace under a single point
of view the many modes of reproduction by gemmation, division, and
sexual union, the reparation of lost parts, variation, inheritance,
reversion, and other such phenomena. Towards the close of the second
volume I shall attempt to connect these facts together by the
hypothesis of pangenesis.
In the early half of the present chapter I have given a long list of
plants in which through bud-variation, that is, independently of
reproduction by seed, the fruit has suddenly become modified in size,
colour, flavour, hairiness, shape, and time of maturity; flowers have
similarly changed in shape, colour, in being double, and greatly in the
character of the calyx; young branches or shoots have changed in
colour, in bearing spines and in habit of growth, as in climbing or in
weeping; leaves have changed in becoming variegated, in shape, period
of unfolding, and in their arrangement on the axis. Buds of all kinds,
whether produced on ordinary branches or on subterranean stems, whether
simple or much modified and supplied with a stock of nutriment, as in
tubers and bulbs, are all liable to sudden variations of the same
general nature.
In the list, many of the cases are certainly due to reversion to
characters not acquired from a cross, but which were formerly present
and have since been lost for a longer or shorter time;—as when a bud on
a variegated plant produces plain leaves, or when the
variously-coloured flowers of the Chrysanthemum revert to the
aboriginal yellow tint. Many other cases included in the list are
probably due to the plants being of crossed parentage, and to the buds
reverting either completely or by segments to one of the two
parent-forms.[154]
We may suspect that the strong tendency in the Chrysanthemum to produce
by bud-variation differently-coloured flowers, results from the
varieties having been at some time intentionally or accidentally
crossed; and this is certainly the case with some kinds of Pelargonium.
So it may be to a large extent with the bud-varieties of the Dahlia,
and with the “broken colours” of Tulips. When, however, a plant reverts
by bud-variation to its two parent forms, or to one of them, it
sometimes does not revert perfectly, but assumes a somewhat new
character,—of which fact, instances have been given, and Carrière
gives[155] another in the cherry.
Many cases of bud-variation, however, cannot be attributed to
reversion, but to so-called spontaneous variability, as is so common
with cultivated plants raised from seed. As a single variety of the
Chrysanthemum has produced by buds six other varieties, and as one
variety of the gooseberry has borne at the same time four distinct
kinds of fruit, it is scarcely possible to believe that all these
variations are due to reversion. We can hardly believe, as remarked in
a previous chapter, that all the many peaches which have yielded
nectarine-buds are of crossed parentage. Lastly, in such cases as that
of the moss-rose, with its peculiar calyx, and of the rose which bears
opposite leaves, in that of the Imatophyllum, etc., there is no known
natural species or variety from which the characters in question could
have been derived by a cross. We must attribute all such cases to the
appearance of absolutely new characters in the buds. The varieties
which have thus arisen cannot be distinguished by any external
character from seedlings; this is notoriously the case with the
varieties of the Rose, Azalea, and many other plants. It deserves
notice that all the plants which have yielded bud-variations have
likewise varied greatly by seed.
The plants which have varied by buds belong to so many orders that we
may infer that almost every plant would be liable to variation, if
placed under the proper exciting conditions. These conditions, as far
as we can judge, mainly depend on long-continued and high cultivation;
for almost all the plants in the foregoing list are perennials, and
have been largely propagated in many soils, under different climates,
by cuttings, offsets, bulbs, tubers, and especially by budding or
grafting. The instances of annuals varying by buds, or producing on the
same plant differently coloured flowers, are comparatively rare:
Hopkirk[156] has seen this with _ Convolvulus tricolor_; and it is not
uncommon with the Balsam and annual Delphinium. According to Sir R.
Schomburgk, plants from the warmer temperate regions, when cultivated
under the hot climate of St. Domingo, are eminently liable to
bud-variation. I am informed by Mr. Sedgwick that moss-roses which have
often been taken to Calcutta always there lose their mossiness; but
change of climate is by no means a necessary contingent, as we see with
the gooseberry, currant, and in many other cases. Plants living under
their natural conditions are very rarely subject to bud-variation.
Variegated leaves have, however, been observed under such
circumstances; and I have given an instance of variation by buds on an
ash-tree planted in ornamental grounds, but it is doubtful whether such
a tree can be considered as living under strictly natural conditions.
Gärtner has seen white and dark-red flowers produced from the same root
of the wild _Achillea millefolium_; and Prof. Caspary has seen a
completely wild _ Viola lutea_ bearing flowers of two different colours
and sizes.[157]
As wild plants are so rarely liable to bud-variation, whilst highly
cultivated plants long propagated by artificial means have yielded many
varieties by this form of reproduction, we are led through a series
such as the following,—namely, all the eyes in the same tuber of the
potato varying in the same manner,—all the fruit on a purple plum-tree
suddenly becoming yellow,—all the fruit on a double-flowered almond
suddenly becoming peach like,—all the buds on grafted trees being in a
very slight degree affected by the stock on which they have been
worked,—all the flowers on a transplanted heartsease changing for a
time in colour, size, and shape,—we are led by such a series to look at
every case of bud-variation as the direct result of the conditions of
life to which the plant has been exposed. On the other hand, plants of
the same variety may be cultivated in two adjoining beds, apparently
under exactly the same conditions, and those in the one bed, as
Carrière insists,[158] will produce many bud-variations, and those in
the other not a single one. Again, if we look to such cases as that of
a peach-tree which, after having been cultivated by tens of thousands
during many years in many countries, and after having annually produced
millions of buds, all of which have apparently been exposed to
precisely the same conditions, yet at last suddenly produces a single
bud with its whole character greatly transformed, we are driven to the
conclusion that the transformation stands in no _direct_ relation to
the conditions of life.
We have seen that varieties produced from seeds and from buds resemble
each other so closely in general appearance that they cannot be
distinguished. Just as certain species and groups of species, when
propagated by seed, are more variable than other species or genera, so
it is in the case of certain bud-varieties. Thus, the Queen of England
Chrysanthemum has produced by this latter process no less than six, and
Rollisson’s Unique Pelargonium four distinct varieties; moss-roses have
also produced several other moss-roses. The Rosaceæ have varied by buds
more than any other group of plants; but this may be in large part due
to so many members having been long cultivated; but within this same
group, the peach has often varied by buds, whilst the apple and pear,
both grafted trees extensively cultivated, have afforded, as far as I
can ascertain, extremely few instances of bud-variation.
The law of analogous variation holds good with varieties produced by
buds, as with those produced from seed: more than one kind of rose has
sported into a moss-rose; more than one kind of camellia has assumed an
hexagonal form; and at least seven or eight varieties of the peach have
produced nectarines.
The laws of inheritance seem to be nearly the same with seminal and
bud-varieties. We know how commonly reversion comes into play with
both, and it may affect the whole, or only segments of a leaf, flower,
or fruit. When the tendency to reversion affects many buds on the same
tree, it becomes covered with different kinds of leaves, flowers, or
fruit; but there is reason to believe that such fluctuating varieties
have generally arisen from seed. It is well known that, out of a number
of seedling varieties, some transmit their character much more truly by
seed than others; so with bud-varieties, some retain their character by
successive buds more truly than others; of which instances have been
given with two kinds of variegated Euonymus and with certain kinds of
tulips and pelargoniums. Notwithstanding the sudden production of
bud-varieties, the characters thus acquired are sometimes capable of
transmission by seminal reproduction: Mr. Rivers has found that
moss-roses generally reproduce themselves by seed; and the mossy
character has been transferred by crossing from one species of rose to
another. The Boston nectarine, which appeared as a bud-variation,
produced by seed a closely allied nectarine. On the other hand,
seedlings from some bud-variations have proved variable to an extreme
degree.[159] We have also heard, on the authority of Mr. Salter, that
seeds taken from a branch with leaves variegated through bud-variation,
transmit this character very feebly; whilst many plants, which were
variegated as seedlings, transmit variegation to a large proportion of
their progeny.
Although I have been able to collect a good many cases of
bud-variation, as shown in the previous lists, and might probably, by
searching foreign horticultural works, have collected very many more
cases, yet their total number is as nothing in comparison with that of
seminal varieties. With seedlings raised from the more variable
cultivated plants, the variations are almost infinitely numerous, but
their differences are generally slight: only at long intervals of time
a strongly marked modification appears. On the other hand, it is a
singular and inexplicable fact that, when plants vary by buds, the
variations, though they occur with comparative rarity, are often, or
even generally, strongly pronounced. It struck me that this might
perhaps be a delusion, and that slight changes often occurred in buds,
but were overlooked or not recorded from being of no value.
Accordingly, I applied to two great authorities on this subject,
namely, to Mr. Rivers with respect to fruit-trees, and to Mr. Salter
with respect to flowers. Mr. Rivers is doubtful, but does not remember
having noticed very slight variations in fruit-buds. Mr. Salter informs
me that with flowers such do occur, but, if propagated, they generally
lose their new character in the following year; yet he concurs with me
that bud-variations usually at once assume a decided and permanent
character. We can hardly doubt that this is the rule, when we reflect
on such cases as that of the peach, which has been so carefully
observed, and of which such trifling seminal varieties have been
propagated, yet this tree has repeatedly produced by bud-variation
nectarines, and only twice (as far as I can learn) any other variety,
namely, the Early and Late Grosse Mignonne peaches; and these differ
from the parent-tree in hardly any character except the period of
maturity.
To my surprise, I hear from Mr. Salter that he brings the principle of
selection to bear on variegated plants propagated by buds, and has thus
greatly improved and fixed several varieties. He informs me that at
first a branch often produces variegated leaves on one side alone, and
that the leaves are marked only with an irregular edging or with a few
lines of white and yellow. To improve and fix such varieties, he finds
it necessary to encourage the buds at the bases of the most distinctly
marked leaves, and to propagate from them alone. By following with
perseverance this plan during three or four successive seasons, a
distinct and fixed variety can generally be secured.
Finally, the facts given in this chapter prove in how close and
remarkable a manner the germ of a fertilised seed and the small
cellular mass forming a bud, resemble each other in all their
functions—in their power of inheritance with occasional reversion,—and
in their capacity for variation of the same general nature, in
obedience to the same laws. This resemblance, or rather identity of
character, is shown in the most striking manner by the fact that the
cellular tissue of one species or variety, when budded or grafted on
another, may give rise to a bud having an intermediate character. We
have seen that variability does not depend on sexual generation, though
much more frequently its concomitant than of bud reproduction. We have
seen that bud-variability is not solely dependent on reversion or
atavism to long-lost characters, or to those formerly acquired from a
cross, but appears often to be spontaneous. But when we ask ourselves
what is the cause of any particular bud-variation, we are lost in
doubt, being driven in some cases to look to the direct action of the
external conditions of life as sufficient, and in other cases to feel a
profound conviction that these have played a quite subordinate part, of
not more importance than the nature of the spark which ignites a mass
of combustible matter.
REFERENCES
[1] Since the publication of the first edition of this work, I have
found that M. Carrière, _Chef des Pépinières au Mus. d’Hist. Nat.,_ in
his excellent Essay ‘Production et Fixation des Variétés, 1865,’ has
given a list of bud-variations far more extensive than mine; but as
these relate chiefly to cases occurring in France I have left my list
as it stood, adding a few facts from M. Carrière and others. Any one
who wishes to study the subject fully should refer to M. Carrière’s
Essay.
[2] ‘Gardener’s Chronicle,’ 1854, p. 821.
[3] Lindley’s ‘Guide to Orchard,’ as quoted in ‘Gardener’s Chronicle,’
1852, p. 821. For the _Early mignonne peach, see_ ‘Gardener’s
Chronicle,’ 1864, p. 1251.
[4] ‘Transact. Hort. Soc.,’ vol. ii. p. 160.
[5] _See also_ ‘Gardener’s Chronicle,’ 1863, p. 27.
[6] ‘Gardener’s Chronicle,’ 1852, p. 821.
[7] ‘Gardener’s Chronicle,’ 1852, p. 629; 1856, p. 648; 1864, p. 986.
Other cases are given by Braun ‘Rejuvenescence,’ in ‘Ray Soc. Bot.
Mem.,’ 1853, p. 314.
[8] ‘Ampélographie,’ etc., 1849, p. 71.
[9] ‘Gardener’s Chronicle,’ 1866, p. 970.
[10] ‘Gardener’s Chronicle,’ 1855, pp. 597, 612.
[11] ‘Gardener’s Chronicle,’ 1842, p. 873; 1855, p. 646. In the
‘Chronicle,’ p. 876, Mr. P. Mackenzie states that the bush still
continues to bear the three kinds of fruit, “although they have not
been every year alike.”
[12] ‘Revue Horticole,’ quoted in ‘Gardener’s Chronicle,’ 1844, p. 87.
[13] ‘Rejuvenescence in Nature,’ ‘Bot. Memoirs Ray Soc.,’ 1853, p.
314.
[14] ‘Comptes Rendus,’ tom. xli. 1855, p. 804. The second case is
given on the authority of Gaudichaud, ibid., tom. xxxiv. 1852, p. 748.
[15] This case is given in the ‘Gardener’s Chronicle,’ 1867, p. 403.
[16] ‘Journal of Proc. Linn. Soc.,’ vol ii. Botany, p. 131.
[17] ‘Gardener’s Chronicle,’ 1847, p. 207.
[18] Herbert, ‘Amaryllidaceæ,’ 1838, p. 369.
[19] ‘Gardener’s Chronicle,’ 1843, p. 391.
[20] Exhibited at Hort. Soc. London. Report in ‘Gardener’s Chronicle,’
1844, p. 337.
[21] Mr. W. Bell ‘Bot. Soc. of Edinburgh,’ May, 1863.
[22] ‘Revue Horticole,’ quoted in ‘Gardener’s Chronicle,’ 1845, p.
475.
[23] ‘Bastarderzeugung,’ 1849, s. 76.
[24] ‘Journal of Horticulture,’ 1861, p. 336.
[25] W. P. Ayres, in ‘Gardener’s Chronicle,’ 1842, p. 791.
[26] W. P. Ayres, ibid.
[27] Dr. Maxwell Masters, ‘Pop. Science Review,’ July, 1872, p. 250.
[28] ‘Gardener’s Chronicle,’ 1861, p. 968.
[29] Ibid., 1861 p. 945.
[30] W. Paul, in ‘Gardener’s Chronicle,’ 1861, p. 968.
[31] Ibid., p. 945.
[32] For other cases of bud-variation in this same variety, _ see_
‘Gardener’s Chronicle,’ 1861, pp. 578, 600, 925. For other distinct
cases of bud-variation in the genus Pelargonium _see_ ‘Cottage
Gardener,’ 1860, p. 194.
[33] Dr. Maxwell Masters, ‘Pop. Science Review,’ July, 1872, p. 254.
[34] Rev. W. T. Bree, in Loudon’s ‘Gardener’s Mag.,’ vol. viii. 1832,
p. 93.
[35] ‘The Chrysanthemum: its History and Culture,’ by J. Salter, 1865,
p. 41, etc.
[36] Bree, in Loudon’s ‘Gardener’s Mag.,’ vol. viii. 1832, p. 93.
[37] Bronn ‘Geschichte der Natur,’ B. ii. s. 123.
[38] T. Rivers, ‘Rose Amateur’s Guide ‘ 1837 p. 4.
[39] Mr. Shailer, quoted in ‘Gardener’s Chronicle,’ 1848 p. 759.
[40] ‘Transact. Hort. Soc.,’ vol. iv. 1822, p. 137; ‘Gardener’s
Chronicle,’ 1842, p. 422.
[41] _See also_ Loudon’s ‘Arboretum,’ vol. ii. p. 780.
[42] All these statements on the origin of the several varieties of
the moss-rose are given on the authority of Mr. Shailer, who, together
with his father, was concerned in their original propagation. _See_
‘Gardener’s Chronicle,’ 1852, p. 759.
[43] ‘Gardener’s Chronicle,’ 1845, p. 564.
[44] ‘Transact. Hort. Soc.,’ vol. ii. p. 242.
[45] ‘Shriften der Phys. Oekon. Gesell. zu Königsberg,’ Feb. 3rd,
1865, s. 4. _See also_ Dr. Caspary’s paper in ‘Transactions of the
Hort. Congress of Amsterdam,’ 1865.
[46] ‘Gardener’s Chronicle,’ 1852, p. 759.
[47] ‘Transact. Hort. Soc.,’ vol. ii. p. 242.
[48] Sir R. Schomburgk, ‘Proc. Linn. Soc. Bot.,’ vol. ii. p. 132.
[49] ‘Gardener’s Chronicle,’ 1862, p. 619.
[50] Hopkirk’s ‘Flora Anomala,’ 167.
[51] ‘Sur La Production et la Fixation des Variétés,’ 1865, p. 4.
[52] ‘Journal of Horticulture,’ March, 1865, p. 233.
[53] ‘Gardener’s Chronicle,’ 1843, p. 135.
[54] Ibid., 1842, p. 55.
[55] ‘Gardener’s Chronicle,’ 1867, p. 235.
[56] Gärtner ‘Bastarderzeugung,’ s. 305.
[57] Mr. D. Beaton, in ‘Cottage Gardener,’ 1860, p. 250.
[58] ‘Gardener’s Chronicle,’ 1850, p. 536.
[59] Braun, ‘Ray Soc. Bot. Mem.,’ 1853, p. 315; Hopkirk’s ‘Flora
Anomala,’ p. 164; Lecoq ‘Géograph. Bot. de l’Europe,’ tom. iii. 1854,
p. 405; and ‘De la Fécondation,’ 1862, p. 303.
[60] ‘Des Variétés,’ 1865, p. 5.
[61] W. Mason, in ‘Gardener’s Chronicle,’ 1843, p. 878.
[62] Alex. Braun, ‘Ray Soc. Bot. Mem.,’ 1853, p. 315; ‘Gardener’s
Chronicle,’ 1841, p. 329.
[63] Dr. M. T. Masters, ‘Royal Institution Lecture,’ March 16th, 1860.
[64] _See_ Mr. W. K. Bridgeman’s curious paper in ‘Annals and Mag. of
Nat. Hist.,’ Dec. 1861; also Mr. J. Scott, ‘Bot. Soc. Edinburgh,’ June
12th, 1862.
[65] ‘Journal of Horticulture,’ 1861, p. 336; Verlot, ‘Des Variétés,’
p. 76.
[66] _See also_ Verlot, ‘Des Variétés,’ p. 74.
[67] ‘Gardener’s Chronicle,’ 1844, p. 86.
[68] Ibid., 1861, p. 963.
[69] Ibid., 1861, p. 433; ‘Cottage Gardener,’ 1860, p. 2.
[70] M. Lemoine (quoted in ‘Gardener’s Chronicle,’ 1867, p. 74) has
lately observed that the Symphytum with variegated leaves cannot be
propagated by division of the roots. He also found that out of 500
plants of a Phlox with striped flowers, which had been propagated by
root-division, only seven or eight produced striped flowers. _See
also_ on striped Pelargoniums, ‘Gardener’s Chronicle,’ 1867, p. 1000.
[71] Anderson’s ‘Recreations in Agriculture,’ vol. v. p. 152.
[72] For wheat, _see_ ‘Improvement of the Cereals,’ by P. Shirreff,
1873, p. 47. For maize and sugar-cane, Carrière, ibid., pp. 40, 42.
With respect to the sugar-cane Mr. J. Caldwell of Mauritius, says
(‘Gardener’s Chronicle,’ 1874, p. 316) the Ribbon cane has here
“sported into a perfectly green cane and a perfectly red cane from the
same head. I verified this myself, and saw at least 200 instances in
the same plantation, and the fact has completely upset all our
preconceived ideas of the difference of colour being permanent. The
conversion of a striped cane into a green cane was not uncommon, but
the change into a red cane universally disbelieved, and that both
events should occur in the same plant incredible. I find, however, in
Fleischman’s ‘Report on Sugar Cultivation in Louisiana for 1848,’ by
the American Patent Office, the circumstance is mentioned, but he says
he never saw it himself.”
[73] ‘Gardener’s Chronicle,’ 1857, p. 662.
[74] ‘Gardener’s Chronicle,’ 1841, p. 814.
[75] Ibid., 1857, p. 613.
[76] Ibid., 1857, p. 679. _See also_ Philips ‘Hist. of Vegetables,’
vol. ii. p. 91, for other and similar accounts.)
[77] ‘Journal of Proc. Linn. Soc.,’ vol. ii. Botany, p. 132.
[78] Loudon’s ‘Gardener’s Mag.,’ vol. viii. 1832, p. 94.
[79] ‘Gardener’s Chronicle,’ 1850, p. 536; and 1842, p. 729.
[80] ‘Des Jacinthes,’ etc., Amsterdam, 1768, p. 122.
[81] ‘Gardener’s Chronicle.’ 1845. p. 212.
[82] Loudon’s ‘Encyclopædia of Gardening,’ p. 1024.
[83] ‘Production des Variétés,’ 1865, p. 63.
[84] ‘Gardener’s Chronicle,’ 1841, p. 782; 1842, p. 55.
[85] ‘Gardener’s Chronicle,’ 1849. p. 565.
[86] ‘Transact. Lin. Soc.,’ vol. ii. p. 354.
[87] Godron, ‘De l’Espèce,’ tom. ii. p. 84.
[88] M. Carrière has lately described in the ‘Revue Horticole,’ (Dec.
1st, 1866, p. 457,) an extraordinary case. He twice inserted grafts of
the _Aria vestita_ on thorn-trees (_épines_) growing in pots; and the
grafts, as they grew, produced shoots with bark, buds, leaves,
petioles, petals, and flower-stalks, all widely different from those
of the Aria. The grafted shoots were also much hardier, and flowered
earlier, than those on the ungrafted Aria.
[89] ‘Transact. Hort. Soc.,’ vol. ii. p. 160.
[90] For the cases of oaks _see_ Alph. De Candolle in ‘Bibl.
Univers.,’ Geneva, Nov. 1862; for limes, etc., Loudon’s ‘Gard. Mag.,’
vol. xi. 1835, p. 503.
[91] For analogous facts, _see_ Braun ‘Rejuvenescence,’ in ‘Ray Soc.
Bot. Mem.,’ 1853, p. 320; and ‘Gardener’s Chronicle,’ 1842, p. 397;
also Braun in ‘Sitzungsberichte der Ges. naturforschender Freunde,’
June, 1873, p. 63.
[92] ‘Journal of Hort. Soc.,’ vol. ii. 1847, p. 100.
[93] _See_ ‘Transact. of Hort. Congress of Amsterdam,’ 1865; but I owe
most of the following information to Prof. Caspary’s letters.
[94] ‘Nouvelles Archives du Muséum,’ tom. i. p. 143.
[95] _See_ on this head, Naudin, ibid., p. 141.
[96] Braun, in ‘Bot. Mem. Ray. Soc.,’ 1853, p. 23.
[97] This hybrid has never been described. It is exactly intermediate
in foliage, time of flowering, dark striæ at the base of the standard
petal, hairiness of the ovarium, and in almost every other character,
between _C. laburnum_ and _ alpinus_; but it approaches the former
species more nearly in colour, and exceeds it in the length of the
racemes. We have before seen that 20·3 per cent of its pollen-grains
are ill-formed and worthless. My plant, though growing not above
thirty or forty yards from both parent-species, during some seasons
yielded no good seeds; but in 1866 it was unusually fertile, and its
long racemes produced from one to occasionally even four pods. Many of
the pods contained no good seeds, but generally they contained a
single apparently good seed, sometimes two, and in one case three
seeds. Some of these seeds germinated, and I raised two trees from
them; one resembles the present form; the other has a remarkable dwarf
character with small leaves, but has not yet flowered.
[98] ‘Annales de la Soc. de l’Hort. de Paris,’ tom. vii. 1830, p. 93.
[99] An account was given in the ‘Gardener’s Chronicle’ (1857, pp.
382, 400) of a common laburnum on which grafts of _C. purpureus_ had
been inserted, and which gradually assumed the character of _C.
adami_; but I have little doubt that _C. adami_ had been sold to the
purchaser, who was not a botanist, in the place of _C. purpureus._ I
have ascertained that this occurred in another instance.
[100] Gallesio, ‘Gli Agrumi dei Giard. Bot. Agrar. di. Firenze,’ 1839,
p. 11. In his ‘Traité du Citrus,’ 1811, p. 146, he speaks as if the
compound fruit consisted in part of a lemon, but this apparently was a
mistake.
[101] ‘Gardener’s Chronicle,’ 1855, p. 628. _See also_ Prof. Caspary
in ‘Transact. Hort. Congress of Amsterdam,’ 1865.
[102] Gärtner (‘Bastarderzeugung,’ s. 611) gives many references on
this subject.
[103] A nearly similar account was given by Brabley, in 1724, in his
‘Treatise on Husbandry,’ vol. i. p. 199.
[104] Morren, ‘Bull. de l’Acad. R. des Sciences de Belgique,’ 2de
séries, tom. xxviii. 1869, p. 434. Also Magnus ‘Gesellschaft
naturforschender Freunde, Berlin,’ Feb. 21st, 1871, p. 13; ibid., June
21st, 1870, and Oct. 17th, 1871. Also ‘Bot. Zeitung,’ Feb. 24th, 1871.
[105] Loudon’s ‘Arboretum,’ vol. iv. p. 2595.
[106] ‘Bastarderzeugung,’ s. 619.
[107] Amsterdam, 1768, p. 124.
[108] ‘Gardener’s Chronicle,’ 1860, p. 672, with a woodcut.
[109] _See_ ‘Gardener’s Chronicle,’ 1869, p. 220.
[110] ‘Gardener’s Chronicle,’ 1869, p. 335.
[111] ‘Gardener’s Chronicle,’ 1869, p. 1018, with remarks by Dr.
Masters on the adhesion of the united wedges. _See also_ ibid., 1870,
pp. 1277, 1283.
[112] ‘Gardener’s Chronicle,’ 1871, p. 837.
[113] ‘Gardener’s Chronicle,’ 1870, p. 1506.
[114] ‘Sitzungsberichte der Gesellschaft naturforschender Freunde zu
Berlin,’ Oct. 17th, 1871.
[115] Ibid., Nov. 17th, 1874. _See also_ excellent remarks by Herr
Magnus.
[116] ‘Bastarderzeugung,’ s. 549. It is, however, doubtful whether
these plants should be ranked as species or varieties.
[117] Gärtner, ibid., s. 550.
[118] ‘Journal de Physique,’ tom. xxiii. 1873, p. 100. ‘Act. Acad. St.
Petersburgh,’ 1781, part i. p. 249.
[119] ‘Nouvelles Archives du Muséum,’ tom. i. p. 49.
[120] L’Hermès, Jan. 14th, 1837, quoted in Loudon’s ‘Gardener’s Mag.,’
vol. xiii. p. 230.
[121] ‘Comptes Rendus,’ tom. xxxiv. 1852, p. 746.
[122] ‘Géograph. Bot. de l’Europe,’ tom. iii. 1854, p. 405; and ‘De la
Fécondation,’ 1862, p. 302.
[123] ‘Traité du Citrus,’ 1811, p. 45.
[124] ‘Transact. Linn. Soc.,’ vol. ix. p. 268.
[125] ‘Annals and Mag. of Nat. Hist.,’ March, 1848.
[126] ‘Pomologie Physiolog.,’ 1830, p. 126.
[127] ‘Philosophical Transact.,’ vol. xliii. 1744-45, p. 525.
[128] Mr. Goss, ‘Transact. Hort. Soc.,’ vol. v. p. 234: and Gärtner,
‘Bastarderzeugung,’ 1849, ss. 81 and 499.
[129] ‘Gardener’s Chronicle,’ 1854, p. 404.
[130] Ibid., 1866, p. 900.
[131] _See also_ a paper by this observer read before the
International Hort. and Bot. Congress of London, 1866.
[132] ‘Traité du Citrus,’ p. 40.
[133] ‘Transact. Hort. Soc.,’ vol. iii. p. 318. _See also_ vol. v. p.
65.
[134] Prof. Asa Gray, ‘Proc. Acad. Sc.,’ Boston, vol. iv. 1860, p. 21.
I have received statements to the same effect from other persons in
the United States.
[135] For the French case _see_ ‘Journ. Hort. Soc.,’ vol. i. new
series, 1866, p. 50. For Germany, _see_ M. Jack quoted in Henfrey’s
‘Botanical Gazette,’ vol. i. p. 277. A case in England has recently
been alluded to by the Rev. J. M. Berkeley before the Hort. Soc. of
London.
[136] ‘Philosophical Transactions,’ vol. xlvii. 1751-52, p. 206.
[137] Gallesio, ‘Teoria della Riproduzione,’ 1816, p. 95.
[138] ‘Bot. Zeitung,’ May, 1868, p. 326.
[139] _See_ Dr. J. Stockton-Hough, in ‘American Naturalist,’ Jan.
1874, p. 29.
[140] ‘Transact. Hort. Soc.,’ vol. v. p. 69.
[141] ‘Bull. de l’Acad. Imp. de St. Petersburg,’ tom. xvii. p. 275,
1872. The author gives references to those cases in the Solanaceæ of
fruit affected by foreign pollen, but as it does not appear that the
mother-plant was artificially fertilised, I have not entered into
details.
[142] ‘Bot. Zeitung,’ Sept. 1868, p. 631. For Maximowicz’s judgment,
_see_ the paper last referred to.
[143] ‘Journal of Horticulture,’ Jan. 20th, 1863, p. 46.
[144] _See_ on this head the high authority of Prof. Decaisne, in a
paper translated in ‘Journ. Hort. Soc.,’ vol. i., new series, 1866, p.
48.
[145] Vol. xliii., 1744-45, p. 525; vol. xlv., 1747-48, p. 602.
[146] ‘Transact. Hort. Soc.,’ vol. v. pp. 65 and 68. _See also_ Prof.
Hildebrand, with a coloured figure, in ‘Bot. Zeitung,’ May 15th, 1868,
p. 327. Puvis also has collected, ‘De La Dégénération,’ 1837, p.
36)several other instances; but it is not in all cases possible to
distinguish between the direct action of foreign pollen and
bud-variations.
[147] T. de Clermont-Tonnerre, in ‘Mém. de la Soc. Linn. de Paris,’
tom. iii. 1825, p. 164.
[148] ‘Transact. of Hort. Soc.,’ vol. v. p. 68.
[149] ‘Beiträge zur Kenntniss der Befruchtung,’ 1844, s. 347-351.
[150] ‘Die Fruchtbildung der Orchideen, ein Beweis für die doppelte
Wirkung des Pollens,’ ‘Botanische Zeitung,’ No. 44 et seq., Oct. 30th,
1865; and Aug. 4th, 1865, s. 249.
[151] ‘Philos. Transact.,’ 1821, p. 20.
[152] Dr. Alex. Harvey on ‘A remarkable Effect of Cross-breeding,’
1851. On the ‘Physiology of Breeding,’ by Mr. Reginald Orton, 1855.
‘Intermarriage,’ by Alex. Walker, 1837. ‘L’Hérédité Naturelle,’ by Dr.
Prosper Lucas, tom. ii. p. 58. Mr. W. Sedgwick, in ‘British and
Foreign Medico-Chirurgical Review,’ 1863, July, p. 183. Bronn, in his
‘Geschichte der Natur,’ 1843, B. ii. s. 127, has collected several
cases with respect to mares, sows, and dogs. Mr. W. C. L. Martin
(‘History of the Dog,’ 1845, p. 104) says he can personally vouch for
the influence of the male parent on subsequent litters by other dogs.
A French poet, Jacques Savary, who wrote in 1665 on dogs, was aware of
this singular fact. Dr. Bowerbank has given us the following striking
case:—A black, hairless Barbary bitch was first accidentally
impregnated by a mongrel spaniel with long brown hair, and she
produced five puppies, three of which were hairless and two covered
with _ short_ brown hair. The next time she was put to a black,
hairless Barbary dog; “but the mischief had been implanted in the
mother, and again about half the litter looked like pure Barbarys, and
the other half like the _short_-haired progeny of the first father.” I
have given in the text one case with pigs; an equally striking one has
been recently published in Germany, ‘Illust. Landwirth. Zeitung,’
1868, Nov. 17th, p. 143. It is worth notice that farmers in S. Brazil
(as I hear from Fritz Müller), and at the C. of Good Hope (as I have
heard from two trustworthy persons) are convinced that mares which
have once borne mules, when subsequently put to horses, are extremely
liable to produce colts, striped like a mule. Dr. Wilckens, of
Pogarth, gives (‘Jahrbuch Landwirthschaft,’ ii. 1869, p. 325) a
striking and analogous case. A merino ram, having two small lappets or
flaps of skin on the neck, was in the winter of 1861-62 put to several
Merino ewes, all of whom bore lambs with similar flaps on their necks.
The ram was killed in the spring of 1862 and subsequently to his death
the ewes were put to other Merino rams, and in 1863 to Southdown rams,
none of whom ever have neck lappets: nevertheless, even as long
afterwards as 1867, several of these ewes produced lambs bearing these
appendages.
[153] ‘Le Pigeon Voyageur Belge,’ 1865, p. 59.
[154] It may be worth while to call attention to the several means by
which flowers and fruit become striped or mottled. Firstly, by the
direct action of the pollen of another variety or species, as in the
cases given of oranges and maize. Secondly, in crosses of the first
generation, when the colours of the two parents do not readily unite,
as with Mirabilis and Dianthus. Thirdly, in crossed plants of a
subsequent generation by reversion, through either bud or seminal
generation. Fourthly, by reversion to a character not originally
gained by a cross, but which had long been lost, as with
white-flowered varieties, which we shall hereafter see often become
striped with some other colour. Lastly, there are cases, as when
peaches are produced with a half or quarter of the fruit like a
nectarine, in which the change is apparently due to mere variation,
through either bud or seminal generation.
[155] ‘Production des Variétés,’ p. 37.
[156] ‘Flora Anomala,’ p. 164.
[157] ‘Schriften der physisch-okon. Gesell. zu Königsberg,’ B. vi.
Feb. 3rd, 1865, s. 4.
[158] ‘Production des Variétés,’ pp. 58, 70.
[159] Carrière, ‘Production des Variétés,’ p. 39.