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Chapter V
ILLEGITIMATE OFFSPRING OF HETEROSTYLED PLANTS.
Illegitimate offspring from all three forms of Lythrum salicaria.
Their dwarfed stature and sterility, some utterly barren, some fertile.
Oxalis, transmission of form to the legitimate and illegitimate seedlings.
Primula Sinensis, Illegitimate offspring in some degree dwarfed and infertile.
Equal-styled varieties of P. Sinensis, auricula, farinosa, and elatior.
P. vulgaris, red-flowered variety, Illegitimate seedlings sterile.
P. veris, Illegitimate plants raised during several successive generations,
their dwarfed stature and sterility.
Equal-styled varieties of P. veris.
Transmission of form by Pulmonaria and Polygonum.
Concluding remarks.
Close parallelism between illegitimate fertilisation and hybridism.
We have hitherto treated of the fertility of the flowers of heterostyled plants,
when legitimately and illegitimately fertilised. The present chapter will be
devoted to the character of their offspring or seedlings. Those raised from
legitimately fertilised seeds will be here called LEGITIMATE SEEDLINGS or
PLANTS, and those from illegitimately fertilised seeds, ILLEGITIMATE SEEDLINGS
or PLANTS. They differ chiefly in their degree of fertility, and in their powers
of growth or vigour. I will begin with trimorphic plants, and I must remind the
reader that each of the three forms can be fertilised in six different ways; so
that all three together can be fertilised in eighteen different ways. For
instance, a long-styled form can be fertilised legitimately by the longest
stamens of the mid-styled and short-styled forms, and illegitimately by its own-
form and mid-length and shortest stamens, also by the mid-length stamens of the
mid-styled and by the shortest stamens of the short-styled form; so that the
long-styled can be fertilised legitimately in two ways and illegitimately in
four ways. The same holds good with respect to the mid-styled and short-styled
forms. Therefore with trimorphic species six of the eighteen unions yield
legitimate offspring, and twelve yield illegitimate offspring.
I will give the results of my experiments in detail, partly because the
observations are extremely troublesome, and will not probably soon be repeated--
thus, I was compelled to count under the microscope above 20,000 seeds of
Lythrum salicaria--but chiefly because light is thus indirectly thrown on the
important subject of hybridism.
Lythrum salicaria.
Of the twelve illegitimate unions two were completely barren, so that no seeds
were obtained, and of course no seedlings could be raised. Seedlings were,
however, raised from seven of the ten remaining illegitimate unions. Such
illegitimate seedlings when in flower were generally allowed to be freely and
legitimately fertilised, through the agency of bees, by other illegitimate
plants belonging to the two other forms growing close by. This is the fairest
plan, and was usually followed; but in several cases (which will always be
stated) illegitimate plants were fertilised with pollen taken from legitimate
plants belonging to the other two forms; and this, as might have been expected,
increased their fertility. Lythrum salicaria is much affected in its fertility
by the nature of the season; and to avoid error from this source, as far as
possible, my observations were continued during several years. Some few
experiments were tried in 1863. The summer of 1864 was too hot and dry, and,
though the plants were copiously watered, some few apparently suffered in their
fertility, whilst others were not in the least affected. The years 1865 and,
especially, 1866, were highly favourable. Only a few observations were made
during 1867. The results are arranged in classes according to the parentage of
the plants. In each case the average number of seeds per capsule is given,
generally taken from ten capsules, which, according to my experience, is a
nearly sufficient number. The maximum number of seeds in any one capsule is also
given; and this is a useful point of comparison with the normal standard--that
is, with the number of seeds produced by legitimate plants legitimately
fertilised. I will give likewise in each case the minimum number. When the
maximum and minimum differ greatly, if no remark is made on the subject, it may
be understood that the extremes are so closely connected by intermediate figures
that the average is a fair one. Large capsules were always selected for
counting, in order to avoid over-estimating the infertility of the several
illegitimate plants.
In order to judge of the degree of inferiority in fertility of the several
illegitimate plants, the following statement of the average and of the maximum
number of seeds produced by ordinary or legitimate plants, when legitimately
fertilised, some artificially and some naturally, will serve as a standard of
comparison, and may in each case be referred to. But I give under each
experiment the percentage of seeds produced by the illegitimate plants, in
comparison with the standard legitimate number of the same form. For instance,
ten capsules from the illegitimate long-styled plant (Number 10), which was
legitimately and naturally fertilised by other illegitimate plants, contained on
an average 44.2 seeds; whereas the capsules on legitimate long-styled plants,
legitimately and naturally fertilised by other legitimate plants, contained on
an average 93 seeds. Therefore this illegitimate plant yielded only 47 per cent
of the full and normal complement of seeds.
STANDARD NUMBER OF SEEDS PRODUCED BY LEGITIMATE PLANTS OF THE THREE FORMS, WHEN
LEGITIMATELY FERTILISED.
Long-styled form:
Average number of seeds in each capsule, 93;
Maximum number observed out of twenty-three capsules, 159.
Mid-styled form:
Average number of seeds, 130;
Maximum number observed out of thirty-one capsules, 151.
Short-styled form:
Average number of seeds, 83.5; but we may, for the sake of brevity, say 83;
Maximum number observed out of twenty-five capsules, 112.
CLASSES 1 AND 2. ILLEGITIMATE PLANTS RAISED FROM LONG-STYLED PARENTS FERTILISED
WITH POLLEN FROM THE MID-LENGTH OR THE SHORTEST STAMENS OF OTHER PLANTS OF THE
SAME FORM.
From this union I raised at different times three lots of illegitimate
seedlings, amounting altogether to 56 plants. I must premise that, from not
foreseeing the result, I did not keep a memorandum whether the eight plants of
the first lot were the product of the mid-length or shortest stamens of the same
form; but I have good reason to believe that they were the product of the
latter. These eight plants were much more dwarfed, and much more sterile than
those in the other two lots. The latter were raised from a long-styled plant
growing quite isolated, and fertilised by the agency of bees with its own
pollen; and it is almost certain, from the relative position of the organs of
fructification, that the stigma under these circumstances would receive pollen
from the mid-length stamens.
All the fifty-six plants in these three lots proved long-styled; now, if the
parent-plants had been legitimately fertilised by pollen from the longest
stamens of the mid-styled and short-styled forms, only about one-third of the
seedlings would have been long-styled, the other two-thirds being mid-styled and
short-styled. In some other trimorphic and dimorphic genera we shall find the
same curious fact, namely, that the long-styled form, fertilised illegitimately
by its own-form pollen, produces almost exclusively long-styled seedlings. (5/1.
Hildebrand first called attention to this fact in the case of Primula Sinensis
('Botanische Zeitung' January 1, 1864 page 5); but his results were not nearly
so uniform as mine.)
The eight plants of the first lot were of low stature: three which I measured
attained, when fully grown, the heights of only 28, 29, and 47 inches; whilst
legitimate plants growing close by were double this height, one being 77 inches.
They all betrayed in their general appearance a weak constitution; they flowered
rather later in the season, and at a later age than ordinary plants. Some did
not flower every year; and one plant, behaving in an unprecedented manner, did
not flower until three years old. In the two other lots none of the plants grew
quite to their full and proper height, as could at once be seen by comparing
them with the adjoining rows of legitimate plants. In several plants in all
three lots, many of the anthers were either shrivelled or contained brown and
tough, or pulpy matter, without any good pollen-grains, and they never shed
their contents; they were in the state designated by Gartner as contabescent,
which term I will for the future use. (5/2. 'Beitrage zur Kenntniss der
Befruchtung' 1844 page 116.) In one flower all the anthers were contabescent
excepting two which appeared to the naked eye sound; but under the microscope
about two-thirds of the pollen-grains were seen to be small and shrivelled. In
another plant, in which all the anthers appeared sound, many of the pollen-
grains were shrivelled and of unequal sizes. I counted the seeds produced by
seven plants (1 to 7) in the first lot of eight plants, probably the product of
parents fertilised by their own-form shortest stamens, and the seeds produced by
three plants in the other two lots, almost certainly the product of parents
fertilised by their own-form mid-length stamens.
[PLANT 1.
This long-styled plant was allowed during 1863 to be freely and legitimately
fertilised by an adjoining illegitimate mid-styled plant, but it did not yield a
single seed-capsule. It was then removed and planted in a remote place close to
a brother long-styled plant Number 2, so that it must have been freely though
illegitimately fertilised; under these circumstances it did not yield during
1864 and 1865 a single capsule. I should here state that a legitimate or
ordinary long-styled plant, when growing isolated, and freely though
illegitimately fertilised by insects with its own pollen, yielded an immense
number of capsules, which contained on an average 21.5 seeds.
PLANT 2.
This long-styled plant, after flowering during 1863 close to an illegitimate
mid-styled plant, produced less than twenty capsules, which contained on an
average between four and five seeds. When subsequently growing in company with
Number 1, by which it will have been illegitimately fertilised, it yielded in
1866 not a single capsule, but in 1865 it yielded twenty-two capsules: the best
of these, fifteen in number, were examined; eight contained no seed, and the
remaining seven contained on an average only three seeds, and these seeds were
so small and shrivelled that I doubt whether they would have germinated.
PLANTS 3 AND 4.
These two long-styled plants, after being freely and legitimately fertilised
during 1863 by the same illegitimate mid-styled plant as in the last case, were
as miserably sterile as Number 2.
PLANT 5.
This long-styled plant, after flowering in 1863 close to an illegitimate mid-
styled plant, yielded only four capsules, which altogether included only five
seeds. During 1864, 1865, and 1866, it was surrounded either by illegitimate or
legitimate plants of the other two forms; but it did not yield a single capsule.
It was a superfluous experiment, but I likewise artificially fertilised in a
legitimate manner twelve flowers; but not one of these produced a capsule; so
that this plant was almost absolutely barren.
PLANT 6.
This long-styled plant, after flowering during the favourable year of 1866,
surrounded by illegitimate plants of the other two forms, did not produce a
single capsule.
PLANT 7.
This long-styled plant was the most fertile of the eight plants of the first
lot. During 1865 it was surrounded by illegitimate plants of various parentage,
many of which were highly fertile, and must thus have been legitimately
fertilised. It produced a good many capsules, ten of which yielded an average of
36.1 seeds, with a maximum of 47 and a minimum of 22; so that this plant
produced 39 per cent of the full number of seeds. During 1864 it was surrounded
by legitimate and illegitimate plants of the other two forms; and nine capsules
(one poor one being rejected) yielded an average of 41.9 seeds, with a maximum
of 56 and a minimum of 28; so that, under these favourable circumstances, this
plant, the most fertile of the first lot, did not yield, when legitimately
fertilised, quite 45 per cent of the full complement of seeds.]
In the second lot of plants in the present class, descended from the long-styled
form, almost certainly fertilised with pollen from its own mid-length stamens,
the plants, as already stated, were not nearly so dwarfed or so sterile as in
the first lot. All produced plenty of capsules. I counted the number of seeds in
only three plants, namely Numbers 8, 9, and 10.
[PLANT 8.
This plant was allowed to be freely fertilised in 1864 by legitimate and
illegitimate plants of the other two forms, and ten capsules yielded on an
average 41.1 seeds, with a maximum of 73 and a minimum of 11. Hence this plant
produced only 44 per cent of the full complement of seeds.
PLANT 9.
This long-styled plant was allowed in 1865 to be freely fertilised by
illegitimate plants of the other two forms, most of which were moderately
fertile. Fifteen capsules yielded on an average 57.1 seeds, with a maximum of 86
and a minimum of 23. Hence the plant yielded 61 per cent of the full complement
of seeds.
PLANT 10.
This long-styled plant was freely fertilised at the same time and in the same
manner as the last. Ten capsules yielded an average of 44.2 seeds, with a
maximum of 69 and a minimum of 25; hence this plant yielded 47 per cent of the
full complement of seeds.]
The nineteen long-styled plants of the third lot, of the same parentage as the
last lot, were treated differently; for they flowered during 1867 by themselves
so that they must have been illegitimately fertilised by one another. It has
already been stated that a legitimate long-styled plant, growing by itself and
visited by insects, yielded an average of 21.5 seeds per capsule, with a maximum
of 35; but, to judge fairly of its fertility, it ought to have been observed
during successive seasons. We may also infer from analogy that, if several
legitimate long-styled plants were to fertilise one another, the average number
of seeds would be increased; but how much increased I do not know; hence I have
no perfectly fair standard of comparison by which to judge of the fertility of
the three following plants of the present lot, the seeds of which I counted.
[PLANT 11.
This long-styled plant produced a large crop of capsules, and in this respect
was one of the most fertile of the whole lot of nineteen plants. But the average
from ten capsules was only 35.9 seeds, with a maximum of 60 and a minimum of 8.
PLANT 12.
This long-styled plant produced very few capsules; and ten yielded an average of
only 15.4 seeds, with a maximum of 30 and a minimum of 4.
PLANT 13.
This plant offers an anomalous case; it flowered profusely, yet produced very
few capsules; but these contained numerous seeds. Ten capsules yielded an
average of 71.9 seeds, with a maximum of 95 and a minimum of 29. Considering
that this plant was illegitimate and illegitimately fertilised by its brother
long-styled seedlings, the average and the maximum are so remarkably high that I
cannot at all understand the case. We should remember that the average for a
legitimate plant legitimately fertilised is 93 seeds.]
CLASS 3. ILLEGITIMATE PLANTS RAISED FROM A SHORT-STYLED PARENT FERTILISED WITH
POLLEN FROM OWN-FORM MID-LENGTH STAMENS.
I raised from this union nine plants, of which eight were short-styled and one
long-styled; so that there seems to be a strong tendency in this form to
reproduce, when self-fertilised, the parent-form; but the tendency is not so
strong as with the long-styled. These nine plants never attained the full height
of legitimate plants growing close to them. The anthers were contabescent in
many of the flowers on several plants.
[PLANT 14.
This short-styled plant was allowed during 1865 to be freely and legitimately
fertilised by illegitimate plants descended from self-fertilised mid-, long- and
short-styled plants. Fifteen capsules yielded an average of 28.3 seeds, with a
maximum of 51 and a minimum of 11; hence this plant produced only 33 per cent of
the proper number of seeds. The seeds themselves were small and irregular in
shape. Although so sterile on the female side, none of the anthers were
contabescent.
PLANT 15.
This short-styled plant, treated like the last during the same year, yielded an
average, from fifteen capsules, of 27 seeds, with a maximum of 49 and a minimum
of 7. But two poor capsules may be rejected, and then the average rises to 32.6,
with the same maximum of 49 and a minimum of 20; so that this plant attained 38
per cent of the normal standard of fertility, and was rather more fertile than
the last, yet many of the anthers were contabescent.
PLANT 16.
This short-styled plant, treated like the two last, yielded from ten capsules an
average of 77.8 seeds, with a maximum of 97 and a minimum of 60; so that this
plant produced 94 per cent of the full number of seeds.
PLANT 17.
This, the one long-styled plant of the same parentage as the last three plants,
when freely and legitimately fertilised in the same manner as the last, yielded
an average from ten capsules of 76.3 rather poor seeds, with a maximum of 88 and
a minimum of 57. Hence this plant produced 82 per cent of the proper number of
seeds. Twelve flowers enclosed in a net were artificially and legitimately
fertilised with pollen from a legitimate short-styled plant; and nine capsules
yielded an average of 82.5 seeds, with a maximum of 98 and a minimum of 51; so
that its fertility was increased by the action of pollen from a legitimate
plant, but still did not reach the normal standard.]
CLASS 4. ILLEGITIMATE PLANTS RAISED FROM A MID-STYLED PARENT FERTILISED WITH
POLLEN FROM OWN-FORM LONGEST STAMENS.
After two trials, I succeeded in raising only four plants from this illegitimate
union. These proved to be three mid-styled and one long-styled; but from so
small a number we can hardly judge of the tendency in mid-styled plants when
self-fertilised to reproduce the same form. These four plants never attained
their full and normal height; the long-styled plant had several of its anthers
contabescent.
[PLANT 18.
This mid-styled plant, when freely and legitimately fertilised during 1865 by
illegitimate plants descended from self-fertilised long-, short-, and mid-styled
plants, yielded an average from ten capsules of 102.6 seeds, with a maximum of
131 and a minimum of 63: hence this plant did not produce quite 80 per cent of
the normal number of seeds. Twelve flowers were artificially and legitimately
fertilised with pollen from a legitimate long-styled plant, and yielded from
nine capsules an average of 116.1 seeds, which were finer than in the previous
case, with a maximum of 135 and a minimum of 75; so that, as with Plant 17,
pollen from a legitimate plant increased the fertility, but did not bring it up
to the full standard.
PLANT 19.
This mid-styled plant, fertilised in the same manner and at the same period as
the last, yielded an average from ten capsules of 73.4 seeds, with a maximum of
87 and a minimum of 64: hence this plant produced only 56 per cent of the full
number of seeds. Thirteen flowers were artificially and legitimately fertilised
with pollen from a legitimate long-styled plant, and yielded ten capsules with
an average of 95.6 seeds; so that the application of pollen from a legitimate
plant added, as in the two previous cases, to the fertility, but did not bring
it up to the proper standard.
PLANT 20.
This long-styled plant, of the same parentage with the two last mid-styled
plants, and freely fertilised in the same manner, yielded an average from ten
capsules of 69.6 seeds, with a maximum of 83 and a minimum of 52: hence this
plant produced 75 per cent of the full number of seeds.]
CLASS 5. ILLEGITIMATE PLANTS RAISED FROM A SHORT-STYLED PARENT FERTILISED WITH
POLLEN FROM THE MID-LENGTH STAMENS OF THE LONG-STYLED FORM.
In the four previous classes, plants raised from the three forms fertilised with
pollen from either the longer or shorter stamens of the same form, but generally
not from the same plant, have been described. Six other illegitimate unions are
possible, namely, between the three forms and the stamens in the other two forms
which do not correspond in height with their pistils. But I succeeded in raising
plants from only three of these six unions. From one of them, forming the
present Class 5, twelve plants were raised; these consisted of eight short-
styled, and four long-styled plants, with not one mid-styled. These twelve
plants never attained quite their full and proper height, but by no means
deserved to be called dwarfs. The anthers in some of the flowers were
contabescent. One plant was remarkable from all the longer stamens in every
flower and from many of the shorter ones having their anthers in this condition.
The pollen of four other plants, in which none of the anthers were contabescent,
was examined; in one a moderate number of grains were minute and shrivelled, but
in the other three they appeared perfectly sound. With respect to the power of
producing seed, five plants (Numbers 21 to 25) were observed: one yielded
scarcely more than half the normal number; a second was slightly infertile; but
the three others actually produced a larger average number of seeds, with a
higher maximum, than the standard. In my concluding remarks I shall recur to
this fact, which at first appears inexplicable.
[PLANT 21.
This short-styled plant, freely and legitimately fertilised during 1865 by
illegitimate plants, descended from self-fertilised long-, mid- and short-styled
parents, yielded an average from ten capsules of 43 seeds, with a maximum of 63
and a minimum of 26: hence this plant, which was the one with all its longer and
many of its shorter stamens contabescent, produced only 52 per cent of the
proper number of seeds.
PLANT 22.
This short-styled plant produced perfectly sound pollen, as viewed under the
microscope. During 1866 it was freely and legitimately fertilised by other
illegitimate plants belonging to the present and the following class, both of
which include many highly fertile plants. Under these circumstances it yielded
from eight capsules an average of 100.5 seeds, with a maximum of 123 and a
minimum of 86; so that it produced 121 per cent of seeds in comparison with the
normal standard. During 1864 it was allowed to be freely and legitimately
fertilised by legitimate and illegitimate plants, and yielded an average, from
eight capsules, of 104.2 seeds, with a maximum of 125 and a minimum of 90;
consequently it exceeded the normal standard, producing 125 per cent of seeds.
In this case, as in some previous cases, pollen from legitimate plants added in
a small degree to the fertility of the plant; and the fertility would, perhaps,
have been still greater had not the summer of 1864 been very hot and certainly
unfavourable to some of the plants of Lythrum.
PLANT 23.
This short-styled plant produced perfectly sound pollen. During 1866 it was
freely and legitimately fertilised by the other illegitimate plants specified
under the last experiment, and eight capsules yielded an average of 113.5 seeds,
with a maximum of 123 and a minimum of 93. Hence this plant exceeded the normal
standard, producing no less than 136 per cent of seeds.
PLANT 24.
This long-styled plant produced pollen which seemed under the microscope sound;
but some of the grains did not swell when placed in water. During 1864 it was
legitimately fertilised by legitimate and illegitimate plants in the same manner
as Plant 22, but yielded an average, from ten capsules, of only 55 seeds, with a
maximum of 88 and a minimum of 24, thus attaining 59 per cent of the normal
fertility. This low degree of fertility, I presume, was owing to the
unfavourable season; for during 1866, when legitimately fertilised by
illegitimate plants in the manner described under Number 22, it yielded an
average, from eight capsules, of 82 seeds, with a maximum of 120 and a minimum
of 67, thus producing 88 per cent of the normal number of seeds.
PLANT 25.
The pollen of this long-styled plant contained a moderate number of poor and
shrivelled grains; and this is a surprising circumstance, as it yielded an
extraordinary number of seeds. During 1866 it was freely and legitimately
fertilised by illegitimate plants, as described under Number 22, and yielded an
average, from eight capsules, of 122.5 seeds, with a maximum of 149 and a
minimum of 84. Hence this plant exceeded the normal standard, producing no less
than 131 per cent of seeds.]
CLASS 6. ILLEGITIMATE PLANTS RAISED FROM MID-STYLED PARENTS FERTILISED WITH
POLLEN FROM THE SHORTEST STAMENS OF THE LONG-STYLED FORM.
I raised from this union twenty-five plants, which proved to be seventeen long-
styled and eight mid-styled, but not one short-styled. None of these plants were
in the least dwarfed. I examined, during the highly favourable season of 1866,
the pollen of four plants: in one mid-styled plant, some of the anthers of the
longest stamens were contabescent, but the pollen-grains in the other anthers
were mostly sound, as they were in all the anthers of the shortest stamens; in
two other mid-styled and in one long-styled plant many of the pollen-grains were
small and shrivelled; and in the latter plant as many as a fifth or sixth part
appeared to be in this state. I counted the seeds in five plants (Numbers 26 to
30), of which two were moderately sterile and three fully fertile.
[PLANT 26.
This mid-styled plant was freely and legitimately fertilised, during the rather
unfavourable year 1864, by numerous surrounding legitimate and illegitimate
plants. It yielded an average, from ten capsules, of 83.5 seeds, with a maximum
of 110 and a minimum of 64, thus attaining 64 per cent of the normal fertility.
During the highly favourable year 1866, it was freely and legitimately
fertilised by illegitimate plants belonging to the present Class and to Class 5,
and yielded an average, from eight capsules, of 86 seeds, with a maximum of 109
and a minimum of 61, and thus attained 66 per cent of the normal fertility. This
was the plant with some of the anthers of the longest stamens contabescent as
above mentioned.
PLANT 27.
This mid-styled plant, fertilised during 1864 in the same manner as the last,
yielded an average, from ten capsules, of 99.4 seeds, with a maximum of 122 and
a minimum of 53, thus attaining to 76 per cent of the normal fertility. If the
season had been more favourable, its fertility would probably have been somewhat
greater, but, judging from the last experiment, only in a slight degree.
PLANT 28.
This mid-styled plant, when legitimately fertilised during the favourable season
of 1866, in the manner described under Number 26, yielded an average, from eight
capsules, of 89 seeds, with a maximum of 119 and a minimum of 69, thus producing
68 per cent of the full number of seeds. In the pollen of both sets of anthers,
nearly as many grains were small and shrivelled as sound.
PLANT 29.
This long-styled plant was legitimately fertilised during the unfavourable
season of 1864, in the manner described under Number 26, and yielded an average,
from ten capsules, of 84.6 seeds, with a maximum of 132 and a minimum of 47,
thus attaining to 91 per cent of the normal fertility. During the highly
favourable season of 1866, when fertilised in the manner described under Number
26, it yielded an average, from nine capsules (one poor capsule having been
excluded), of 100 seeds, with a maximum of 121 and a minimum of 77. This plant
thus exceeded the normal standard, and produced 107 per cent of seeds. In both
sets of anthers there were a good many bad and shrivelled pollen-grains, but not
so many as in the last-described plant.
Plant 30.
This long-styled plant was legitimately fertilised during 1866 in the manner
described under Number 26, and yielded an average, from eight capsules, of 94
seeds, with a maximum of 106 and a minimum of 66; so that it exceeded the normal
standard, yielding 101 per cent of seeds.
Plant 31.
Some flowers on this long-styled plant were artificially and legitimately
fertilised by one of its brother illegitimate mid-styled plants; and five
capsules yielded an average of 90.6 seeds, with a maximum of 97 and a minimum of
79. Hence, as far as can be judged from so few capsules, this plant attained,
under these favourable circumstances, 98 per cent of the normal standard.]
CLASS 7. ILLEGITIMATE PLANTS RAISED FROM MID-STYLED PARENTS FERTILISED WITH
POLLEN FROM THE LONGEST STAMENS OF THE SHORT-STYLED FORM.
It was shown in the last chapter that the union from which these illegitimate
plants were raised is far more fertile than any other illegitimate union; for
the mid-styled parent, when thus fertilised, yielded an average (all very poor
capsules being excluded) of 102.8 seeds, with a maximum of 130; and the
seedlings in the present class likewise have their fertility not at all
lessened. Forty plants were raised; and these attained their full height and
were covered with seed-capsules. Nor did I observe any contabescent anthers. It
deserves, also, particular notice that these plants, differently from what
occurred in any of the previous classes, consisted of all three forms, namely,
eighteen short-styled, fourteen long-styled, and eight mid-styled plants. As
these plants were so fertile, I counted the seeds only in the two following
cases.
[PLANT 32.
This mid-styled plant was freely and legitimately fertilised during the
unfavourable year of 1864, by numerous surrounding legitimate and illegitimate
plants. Eight capsules yielded an average of 127.2 seeds, with a maximum of 144
and a minimum of 96; so that this plant attained 98 per cent of the normal
standard.
PLANT 33.
This short-styled plant was fertilised in the same manner and at the same time
with the last; and ten capsules yielded an average of 113.9, with a maximum of
137 and a minimum of 90. Hence this plant produced no less than 137 per cent of
seeds in comparison with the normal standard.]
CONCLUDING REMARKS ON THE ILLEGITIMATE OFFSPRING OF THE THREE FORMS OF Lythrum
salicaria.
From the three forms occurring in approximately equal numbers in a state of
nature, and from the results of sowing seed naturally produced, there is reason
to believe that each form, when legitimately fertilised, reproduces all three
forms in about equal numbers. Now, we have seen (and the fact is a very singular
one) that the fifty-six plants produced from the long-styled form,
illegitimately fertilised with pollen from the same form (Class 1 and 2), were
all long-styled. The short-styled form, when self-fertilised (Class 3), produced
eight short-styled and one long-styled plant; and the mid-styled form, similarly
treated (Class 4), produced three mid-styled and one long-styled offspring; so
that these two forms, when illegitimately fertilised with pollen from the same
form, evince a strong, but not exclusive, tendency to reproduce the parent-form.
When the short-styled form was illegitimately fertilised by the long-styled form
(Class 5), and again when the mid-styled was illegitimately fertilised by the
long-styled (Class 6), in each case the two parent-forms alone were reproduced.
As thirty-seven plants were raised from these two unions, we may, with much
confidence, believe that it is the rule that plants thus derived usually consist
of both parent-forms, but not of the third form. When, however, the mid-styled
form was illegitimately fertilised by the longest stamens of the short-styled
(Class 7), the same rule did not hold good; for the seedlings consisted of all
three forms. The illegitimate union from which these latter seedlings were
raised is, as previously stated, singularly fertile, and the seedlings
themselves exhibited no signs of sterility and grew to their full height. From
the consideration of these several facts, and from analogous ones to be given
under Oxalis, it seems probable that in a state of nature the pistil of each
form usually receives, through the agency of insects, pollen from the stamens of
corresponding height from both the other forms. But the case last given shows
that the application of two kinds of pollen is not indispensable for the
production of all three forms. Hildebrand has suggested that the cause of all
three forms being regularly and naturally reproduced, may be that some of the
flowers are fertilised with one kind of pollen, and others on the same plant
with the other kind of pollen. Finally, of the three forms, the long-styled
evinces somewhat the strongest tendency to reappear amongst the offspring,
whether both, or one, or neither of the parents are long-styled.
[TABLE 5.30. Tabulated results of the fertility of the foregoing illegitimate
plants, when legitimately fertilised, generally by illegitimate plants, as
described under each experiment. Plants 11, 12 and 13 are excluded, as they were
illegitimately fertilised.
NORMAL STANDARD OF FERTILITY OF THE THREE FORMS, WHEN LEGITIMATELY AND NATURALLY
FERTILISED.
Column 1: Form.
Column 2: Average number of seeds per capsule.
Column 3: Maximum number in any one capsule.
Column 4: Minimum number in any one capsule.
Long-styled : 93 : 159 : No record was kept as all very poor capsules were
rejected.
Mid-styled : 130 : 151 : No record was kept as all very poor capsules were
rejected.
Short-styled : 83.5 : 112 : No record was kept as all very poor capsules were
rejected.
TABLE 5.30. Continued.
CLASS 1 AND CLASS 2.--ILLEGITIMATE PLANTS RAISED FROM LONG-STYLED PARENTS
FERTILISED WITH POLLEN FROM OWN-FORM MID-LENGTH OR SHORTEST STAMENS.
Column 1: Number (name) of plant.
Column 2: Form.
Column 3: Average number of seeds per capsule.
Column 4: Maximum number of seeds in any one capsule.
Column 5: Minimum number of seeds in any one capsule.
Column 6: Average number of seeds, expressed as the percentage of the normal
standard.
1 : Long-styled : 0 : 0 : 0 : 0.
2 : Long-styled : 4.5 : ? : 0 : 5.
3 : Long-styled : 4.5 : ? : 0 : 5.
4 : Long-styled : 4.5 : ? : 0 : 5.
5 : Long-styled : 0 or 1 : 2 : 0 : 0 or 1.
6 : Long-styled : 0 : 0 : 0 : 0.
7 : Long-styled : 36.1 : 47 : 22 : 39.
8 : Long-styled : 41.1 : 73 : 11 : 44.
9 : Long-styled : 57.1 : 86 : 23 : 61.
10 : Long-styled : 44.2 : 69 : 25 : 47.
CLASS 3. ILLEGITIMATE PLANTS RAISED FROM SHORT-STYLED PARENTS FERTILISED WITH
POLLEN FROM OWN-FORM SHORTEST STAMENS.
14 : Short-styled : 28.3 : 51 : 11 : 33.
15 : Short-styled : 32.6 : 49 : 20 : 38.
16 : Short-styled : 77.8 : 97 : 60 : 94.
17 : Long-styled : 76.3 : 88 : 57 : 82.
CLASS 4. ILLEGITIMATE PLANTS RAISED FROM MID-STYLED PARENTS FERTILISED WITH
POLLEN FROM OWN-FORM LONGEST STAMENS.
18 : Mid-styled : 102.6 : 131 : 63 : 80.
19 : Mid-styled : 73.4 : 87 : 64 : 56.
20 : Long-styled : 69.6 : 83 : 52 : 75.
CLASS 5. ILLEGITIMATE PLANTS RAISED FROM SHORT-STYLED PARENTS FERTILISED WITH
POLLEN FROM THE MID-LENGTH STAMENS OF THE LONG-STYLED FORM.
21 : Short-styled : 43.0 : 63 : 26 : 52.
22 : Short-styled : 100.5 : 123 : 86 : 121.
23 : Short-styled : 113.5 : 123 : 93 : 136.
24 : Long-styled : 82.0 : 120 : 67 : 88.
25 : Long-styled : 122.5 : 149 : 84 : 131.
CLASS 6. ILLEGITIMATE PLANTS RAISED FROM MID-STYLED PARENTS FERTILISED WITH
POLLEN FROM THE SHORTEST STAMENS OF THE LONG-STYLED FORM.
26 : Mid-styled : 86.0 : 109 : 61 : 66.
27 : Mid-styled : 99.4 : 122 : 53 : 76.
28 : Mid-styled : 89.0 : 119 : 69 : 68.
29 : Long-styled : 100.0 : 121 : 77 : 107.
30 : Long-styled : 94.0 : 106 : 66 : 101.
31 : Long-styled : 90.6 : 97 : 79 : 98.
CLASS 7. ILLEGITIMATE PLANTS RAISED FROM MID-STYLED PARENTS FERTILISED WITH
POLLEN FROM THE LONGEST STAMENS OF THE SHORT-STYLED FORM.
32 : Mid-styled : 127.2 : 144 : 96 : 98.
33 : Short-styled : 113.9 : 137 : 90 : 137.
The lessened fertility of most of these illegitimate plants is in many respects
a highly remarkable phenomenon. Thirty-three plants in the seven classes were
subjected to various trials, and the seeds carefully counted. Some of them were
artificially fertilised, but the far greater number were freely fertilised (and
this is the better and natural plan) through the agency of insects, by other
illegitimate plants. In the right hand, or percentage column, in Table 5.30, a
wide difference in fertility between the plants in the first four and the last
three classes may be perceived. In the first four classes the plants are
descended from the three forms illegitimately fertilised with pollen taken from
the same form, but only rarely from the same plant. It is necessary to observe
this latter circumstance; for, as I have elsewhere shown, most plants, when
fertilised with their own pollen, or that from the same plant, are in some
degree sterile, and the seedlings raised from such unions are likewise in some
degree sterile, dwarfed, and feeble. (5/3. 'The Effects of Cross and Self-
fertilisation in the Vegetable Kingdom' 1876.) None of the nineteen illegitimate
plants in the first four classes were completely fertile; one, however, was
nearly so, yielding 96 per cent of the proper number of seeds. From this high
degree of fertility we have many descending gradations, till we reach an
absolute zero, when the plants, though bearing many flowers, did not produce,
during successive years, a single seed or even seed-capsule. Some of the most
sterile plants did not even yield a single seed when legitimately fertilised
with pollen from legitimate plants. There is good reason to believe that the
first seven plants in Class 1 and 2 were the offspring of a long-styled plant
fertilised with pollen from its own-form shortest stamens, and these plants were
the most sterile of all. The remaining plants in Class 1 and 2 were almost
certainly the product of pollen from the mid-length stamens, and although very
sterile, they were less so than the first set. None of the plants in the first
four classes attained their full and proper stature; the first seven, which were
the most sterile of all (as already stated), were by far the most dwarfed,
several of them never reaching to half their proper height. These same plants
did not flower at so early an age, or at so early a period in the season, as
they ought to have done. The anthers in many of their flowers, and in the
flowers of some other plants in the first six classes, were either contabescent
or included numerous small and shrivelled pollen-grains. As the suspicion at one
time occurred to me that the lessened fertility of the illegitimate plants might
be due to the pollen alone having been affected, I may remark that this
certainly was not the case; for several of them, when fertilised by sound pollen
from legitimate plants, did not yield the full complement of seeds; hence it is
certain that both the female and male reproductive organs were affected. In each
of the seven classes, the plants, though descended from the same parents, sown
at the same time and in the same soil, differed much in their average degree of
fertility.
Turning now to the fifth, sixth, and seventh classes, and looking to the right
hand column of Table 5.30, we find nearly as many plants with a percentage of
seeds above the normal standard as beneath it. As with most plants the number of
seeds produced varies much, it might be thought that the present case was one
merely of variability. But this view must be rejected, as far as the less
fertile plants in these three classes are concerned: first, because none of the
plants in Class 5 attained their proper height, which shows that they were in
some manner affected; and, secondly, because many of the plants in Classes 5 and
6 produced anthers which were either contabescent or included small and
shrivelled pollen-grains. And as in these cases the male organs were manifestly
deteriorated, it is by far the most probable conclusion that the female organs
were in some cases likewise affected, and that this was the cause of the reduced
number of seeds.
With respect to the six plants in these three classes which yielded a very high
percentage of seeds, the thought naturally arises that the normal standard of
fertility for the long-styled and short-styled forms (with which alone we are
here concerned) may have been fixed too low, and that the six legitimate plants
are merely fully fertile. The standard for the long-styled form was deduced by
counting the seeds in twenty-three capsules, and for the short-styled form from
twenty-five capsules. I do not pretend that this is a sufficient number of
capsules for absolute accuracy; but my experience has led me to believe that a
very fair result may thus be gained. As, however, the maximum number observed in
the twenty-five capsules of the short-styled form was low, the standard in this
case may possibly be not quite high enough. But it should be observed, in the
case of the illegitimate plants, that in order to avoid over-estimating their
infertility, ten very fine capsules were always selected; and the years 1865 and
1866, during which the plants in the three latter classes were experimented on,
were highly favourable for seed-production. Now, if this plan of selecting very
fine capsules during favourable seasons had been followed for obtaining the
normal standards, instead of taking, during various seasons, the first capsules
which came to hand, the standards would undoubtedly have been considerably
higher; and thus the fact of the six foregoing plants appearing to yield an
unnaturally high percentage of seeds may, perhaps, be explained. On this view,
these plants are, in fact, merely fully fertile, and not fertile to an abnormal
degree. Nevertheless, as characters of all kinds are liable to variation,
especially with organisms unnaturally treated, and as in the four first and more
sterile classes, the plants derived from the same parents and treated in the
same manner, certainly did vary much in sterility, it is possible that certain
plants in the latter and more fertile classes may have varied so as to have
acquired an abnormal degree of fertility. But it should be noticed that, if my
standards err in being too low, the sterility of all the many sterile plants in
the several classes will have to be estimated by so much the higher. Finally, we
see that the illegitimate plants in the four first classes are all more or less
sterile, some being absolutely barren, with one alone almost completely fertile;
in the three latter classes, some of the plants are moderately sterile, whilst
others are fully fertile, or possibly fertile in excess.
The last point which need here be noticed is that, as far as the means of
comparison serve, some degree of relationship generally exists between the
infertility of the illegitimate union of the several parent-forms and that of
their illegitimate offspring. Thus the two illegitimate unions, from which the
plants in Classes 6 and 7 were derived, yielded a fair amount of seed, and only
a few of these plants are in any degree sterile. On the other hand, the
illegitimate unions between plants of the same form always yield very few seeds,
and their seedlings are very sterile. Long-styled parent-plants when fertilised
with pollen from their own-form shortest stamens, appear to be rather more
sterile than when fertilised with their own-form mid-length stamens; and the
seedlings from the former union were much more sterile than those from the
latter union. In opposition to this relationship, short-styled plants
illegitimately fertilised with pollen from the mid-length stamens of the long-
styled form (Class 5) are very sterile; whereas some of the offspring raised
from this union were far from being highly sterile. It may be added that there
is a tolerably close parallelism in all the classes between the degree of
sterility of the plants and their dwarfed stature. As previously stated, an
illegitimate plant fertilised with pollen from a legitimate plant has its
fertility slightly increased. The importance of the several foregoing
conclusions will be apparent at the close of this chapter, when the illegitimate
unions between the forms of the same species and their illegitimate offspring,
are compared with the hybrid unions of distinct species and their hybrid
offspring.
OXALIS.
No one has compared the legitimate and illegitimate offspring of any trimorphic
species in this genus. Hildebrand sowed illegitimately fertilised seeds of
Oxalis Valdiviana, but they did not germinate (5/4. 'Botanische Zeitung' 1871
page 433 footnote.); and this fact, as he remarks, supports my view that an
illegitimate union resembles a hybrid one between two distinct species, for the
seeds in this latter case are often incapable of germination.
[The following observations relate to the nature of the forms which appear among
the legitimate seedlings of Oxalis Valdiviana. Hildebrand raised, as described
in the paper just referred to, 211 seedlings from all six legitimate unions, and
the three forms appeared among the offspring from each union. For instance,
long-styled plants were legitimately fertilised with pollen from the longest
stamens of the mid-styled form, and the seedlings consisted of 15 long-styled,
18 mid-styled, and 6 short-styled. We here see that a few short-styled plants
were produced, though neither parent was short-styled; and so it was with the
other legitimate unions. Out of the above 211 seedlings, 173 belonged to the
same two forms as their parents, and only 38 belonged to the third form distinct
from either parent. In the case of O. Regnelli, the result, as observed by
Hildebrand, was nearly the same, but more striking: all the offspring from four
of the legitimate unions consisted of the two parent-forms, whilst amongst the
seedlings from the other two legitimate unions the third form appeared. Thus, of
the 43 seedlings from the six legitimate unions, 35 belonged to the same two
forms as their parents, and only 8 to the third form. Fritz Muller also raised
in Brazil seedlings from long-styled plants of O. Regnelli legitimately
fertilised with pollen from the longest stamens of the mid-styled form, and all
these belonged to the two parent-forms. (5/5. 'Jenaische Zeitschrift' etc. Band
6 1871 page 75.) Lastly, seedlings were raised by me from long-styled plants of
O. speciosa legitimately fertilised by the short-styled form, and from the
latter reciprocally fertilised by the long-styled; and these consisted of 33
long-styled and 26 short-styled plants, with not one mid-styled form. There can,
therefore, be no doubt that the legitimate offspring from any two forms of
Oxalis tend to belong to the same two forms as their parents; but that a few
seedlings belonging to the third form occasionally make their appearance; and
this latter fact, as Hildebrand remarks, may be attributed to atavism, as some
of their progenitors will almost certainly have belonged to the third form.
When, however, any one form of Oxalis is fertilised illegitimately with pollen
from the same form, the seedlings appear to belong invariably to this form. Thus
Hildebrand states that long-styled plants of O. rosea growing by themselves have
been propagated in Germany year after year by seed, and have always produced
long-styled plants. (5/6. 'Ueber den Trimorphismus in der Gattung Oxalis:
Monatsberichte der Akad. der Wissen. zu Berlin' 21 June 1866 page 373 and
'Botanische Zeitung' 1871 page 435.) Again, 17 seedlings were raised from mid-
styled plants of O. hedysaroides growing by themselves, and these were all mid-
styled. So that the forms of Oxalis, when illegitimately fertilised with their
own pollen, behave like the long-styled form of Lythrum salicaria, which when
thus fertilised always produced with me long-styled offspring.]
PRIMULA.
Primula Sinensis.
I raised during February 1862, from some long-styled plants illegitimately
fertilised with pollen from the same form, twenty-seven seedlings. These were
all long-styled. They proved fully fertile or even fertile in excess; for ten
flowers, fertilised with pollen from other plants of the same lot, yielded nine
capsules, containing on an average 39.75 seeds, with a maximum in one capsule of
66 seeds. Four other flowers legitimately crossed with pollen from a legitimate
plant, and four flowers on the latter crossed with pollen from the illegitimate
seedlings, yielded seven capsules with an average of 53 seeds, with a maximum of
72. I must here state that I have found some difficulty in estimating the normal
standard of fertility for the several unions of this species, as the results
differ much during successive years, and the seeds vary so greatly in size that
it is hard to decide which ought to be considered good. In order to avoid over-
estimating the infertility of the several illegitimate unions, I have taken the
normal standard as low as possible.
From the foregoing twenty-seven illegitimate plants, fertilised with their own-
form pollen, twenty-five seedling grandchildren were raised; and these were all
long-styled; so that from the two illegitimate generations fifty-two plants were
raised, and all without exception proved long-styled. These grandchildren grew
vigorously, and soon exceeded in height two other lots of illegitimate seedlings
of different parentage and one lot of equal-styled seedlings presently to be
described. Hence I expected that they would have turned out highly ornamental
plants; but when they flowered, they seemed, as my gardener remarked, to have
gone back to the wild state; for the petals were pale-coloured, narrow,
sometimes not touching each other, flat, generally deeply notched in the middle,
but not flexuous on the margin, and with the yellow eye or centre conspicuous.
Altogether these flowers were strikingly different from those of their
progenitors; and this I think, can only be accounted for on the principle of
reversion. Most of the anthers on one plant were contabescent. Seventeen flowers
on the grandchildren were illegitimately fertilised with pollen taken from other
seedlings of the same lot, and produced fourteen capsules, containing on an
average 29.2 seeds; but they ought to have contained about 35 seeds. Fifteen
flowers legitimately fertilised with pollen from an illegitimate short-styled
plant (belonging to the lot next to be described) produced fourteen capsules,
containing an average of 46 seeds; they ought to have contained at least 50
seeds. Hence these grandchildren of illegitimate descent appear to have lost,
though only in a very slight degree, their full fertility.
We will now turn to the short-styled form: from a plant of this kind, fertilised
with its own-form pollen, I raised, during February 1862, eight seedlings, seven
of which were short-styled and one long-styled. They grew slowly, and never
attained to the full stature of ordinary plants; some of them flowered
precociously, and others late in the season. Four flowers on these short-styled
seedlings and four on the one long-styled seedling were illegitimately
fertilised with their own-form pollen and produced only three capsules,
containing on an average 23.6 seeds, with a maximum of 29; but we cannot judge
of their fertility from so few capsules; and I have greater doubts about the
normal standard for this union than about any other; but I believe that rather
above 25 seeds would be a fair estimate. Eight flowers on these same short-
styled plants, and the one long-styled illegitimate plant were reciprocally and
legitimately crossed; they produced five capsules, which contained an average of
28.6 seeds, with a maximum of 36. A reciprocal cross between legitimate plants
of the two forms would have yielded an average of at least 57 seeds, with a
possible maximum of 74 seeds; so that these illegitimate plants were sterile
when legitimately crossed.
I succeeded in raising from the above seven short-styled illegitimate plants,
fertilised with their own-form pollen, only six plants--grandchildren of the
first union. These, like their parents, were of low stature, and had so poor a
constitution that four died before flowering. With ordinary plants it has been a
rare event with me to have more than a single plant die out of a large lot. The
two grandchildren which lived and flowered were short-styled; and twelve of
their flowers were fertilised with their own-form pollen and produced twelve
capsules containing an average of 28.2 seeds; so that these two plants, though
belonging to so weakly a set, were rather more fertile than their parents, and
perhaps not in any degree sterile. Four flowers on the same two grandchildren
were legitimately fertilised by a long-styled illegitimate plant, and produced
four capsules, containing only 32.2 seeds instead of about 64 seeds, which is
the normal average for legitimate short-styled plants legitimately crossed.
By looking back, it will be seen that I raised at first from a short-styled
plant fertilised with its own-form pollen one long-styled and seven short-styled
illegitimate seedlings. These seedlings were legitimately intercrossed, and from
their seed fifteen plants were raised, grandchildren of the first illegitimate
union, and to my surprise all proved short-styled. Twelve short-styled flowers
borne by these grandchildren were illegitimately fertilised with pollen taken
from other plants of the same lot, and produced eight capsules which contained
an average of 21.8 seeds, with a maximum of 35. These figures are rather below
the normal standard for such a union. Six flowers were also legitimately
fertilised with pollen from an illegitimate long-styled plant and produced only
three capsules, containing on an average 23.6 seeds, with a maximum of 35. Such
a union in the case of a legitimate plant ought to have yielded an average of 64
seeds, with a possible maximum of 73 seeds.
SUMMARY ON THE TRANSMISSION OF FORM, CONSTITUTION, AND FERTILITY OF THE
ILLEGITIMATE OFFSPRING OF Primula Sinensis.
In regard to the long-styled plants, their illegitimate offspring, of which
fifty-two were raised in the course of two generations, were all long-styled.
(5/7. Dr. Hildebrand, who first called attention to this subject 'Botanische
Zeitung' 1864 page 5, raised from a similar illegitimate union seventeen plants,
of which fourteen were long-styled and three short-styled. From a short-styled
plant illegitimately fertilised with its own pollen he raised fourteen plants,
of which eleven were short-styled and three long-styled.) These plants grew
vigorously; but the flowers in one instance were small, appearing as if they had
reverted to the wild state. In the first illegitimate generation they were
perfectly fertile, and in the second their fertility was only very slightly
impaired. With respect to the short-styled plants, twenty-four out of twenty-
five of their illegitimate offspring were short-styled. They were dwarfed in
stature, and one lot of grandchildren had so poor a constitution that four out
of six plants perished before flowering. The two survivors, when illegitimately
fertilised with their own-form pollen, were rather less fertile than they ought
to have been; but their loss of fertility was clearly shown in a special and
unexpected manner, namely, when legitimately fertilised by other illegitimate
plants: thus altogether eighteen flowers were fertilised in this manner, and
yielded twelve capsules, which included on an average only 28.5 seeds, with a
maximum of 45. Now a legitimate short-styled plant would have yielded, when
legitimately fertilised, an average of 64 seeds, with a possible maximum of 74.
This particular kind of infertility will perhaps be best appreciated by a
simile: we may assume that with mankind six children would be born on an average
from an ordinary marriage; but that only three would be born from an incestuous
marriage. According to the analogy of Primula Sinensis, the children of such
incestuous marriages, if they continued to marry incestuously, would have their
sterility only slightly increased; but their fertility would not be restored by
a proper marriage; for if two children, both of incestuous origin, but in no
degree related to each other, were to marry, the marriage would of course be
strictly legitimate, nevertheless they would not give birth to more than half
the full and proper number of children.
[EQUAL-STYLED VARIETY OF Primula Sinensis.
As any variation in the structure of the reproductive organs, combined with
changed function, is a rare event, the following cases are worth giving in
detail. My attention was first called to the subject by observing, in 1862, a
long-styled plant, descended from a self-fertilised long-styled parent, which
had some of its flowers in an anomalous state, namely, with the stamens placed
low down in the corolla as in the ordinary long-styled form, but with the
pistils so short that the stigmas stood on a level with the anthers. These
stigmas were nearly as globular and as smooth as in the short-styled form,
instead of being elongated and rough as in the long-styled form. Here, then, we
have combined in the same flower, the short stamens of the long-styled form with
a pistil closely resembling that of the short-styled form. But the structure
varied much even on the same umbel: for in two flowers the pistil was
intermediate in length between that of the long and that of the short-styled
form, with the stigma elongated as in the former, and smooth as in the latter;
and in three other flowers the structure was in all respects like that of the
long-styled form. These modifications appeared to me so remarkable that I
fertilised eight of the flowers with their own pollen, and obtained five
capsules, which contained on an average 43 seeds; and this number shows that the
flowers had become abnormally fertile in comparison with those of ordinary long-
styled plants when self-fertilised. I was thus led to examine the plants in
several small collections, and the result showed that the equal-styled variety
was not rare.
TABLE 5.31. Primula Sinensis. Preponderance of long-styled over the short-styled
form.
Column 1: Name of owner or place.
Column 2: Long-styled form.
Column 3: Short-styled form.
Column 4: equal-styled variety.
Mr. Horwood : 0 : 0 : 17.
Mr. Duck : 20 : 0 : 9.
Baston : 30 : 18 : 15.
Chichester : 12 : 9 : 2.
Holwood : 42 : 12 : 0.
High Elms : 16 : 0 : 0.
Westerham : 1 : 5 : 0.
My own plants from purchased seeds : 13 : 7 : 0.
Total : 134 : 51 : 43.
In a state of nature the long and short-styled forms would no doubt occur in
nearly equal numbers, as I infer from the analogy of the other heterostyled
species of Primula, and from having raised the two forms of the present species
in exactly the same number from flowers which had been LEGITIMATELY crossed. The
preponderance in Table 5.31 of the long-styled form over the short-styled (in
the proportion of 134 to 51) results from gardeners generally collecting seed
from self-fertilised flowers; and the long-styled flowers produce spontaneously
much more seed (as shown in the first chapter) than the short-styled, owing to
the anthers of the long-styled form being placed low down in the corolla, so
that, when the flowers fall off, the anthers are dragged over the stigma; and we
now also know that long-styled plants, when self-fertilised, very generally
reproduce long-styled offspring. From the consideration of this table, it
occurred to me in the year 1862, that almost all the plants of the Chinese
primrose cultivated in England would sooner or later become long-styled or
equal-styled; and now, at the close of 1876, I have had five small collections
of plants examined, and almost all consisted of long-styled, with some more or
less well-characterised equal-styled plants, but with not one short-styled.
With respect to the equal-styled plants in the table, Mr. Horwood raised from
purchased seeds four plants, which he remembered were certainly not long-styled,
but either short or equal-styled, probably the latter. These four plants were
kept separate and allowed to fertilise themselves; from their seed the seventeen
plants in the table were raised, all of which proved equal-styled. The stamens
stood low down in the corolla as in the long-styled form; and the stigmas, which
were globular and smooth, were either completely surrounded by the anthers, or
stood close above them. My son William made drawings for me, by the aid of the
camera, of the pollen of one of the above equal-styled plants; and, in
accordance with the position of the stamens, the grains resembled in their small
size those of the long-styled form. He also examined pollen from two equal-
styled plants at Southampton; and in both of them the grains differed extremely
in size in the same anthers, a large number being small and shrivelled, whilst
many were fully as large as those of the short-styled form and rather more
globular. It is probable that the large size of these grains was due, not to
their having assumed the character of the short-styled form, but to m
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