AMERICAN AGRICULTURIST. 
[June, 
2,22 
ago, by P. J. Berckmans, Esq., of Augusta, Ga., 
In whose extensive nursery it has come into 
bearing. We do not know how far north the 
plant will endure the winter; in Europe the 
tree will live in the north of France, but it 
bears fruit only in the regions where the olive 
succeeds. It is raised from seeds, which are 
very slow in germinating, but more frequently 
from suckers, which come up abundantly 
around the base of the old trees. 
- - — « " —-——— 
How Flowers are Fertilized. 
BY PROF. ASA GRAY. 
ARTICLE V.—DICENTRA OR BLEEDING-HEARTS. 
We have not gone through with half the kinds 
of flowers in which cross fertilization is, in some 
way or another, provided for. But, not to harp too 
long upon one string, we are disposed to vary the 
theme, and to take up a common blossom of our 
gardens at this season, which anybody would say 
was intended to fertilize itself. Dicentra spectabilis, 
one of the commonest, as well as prettiest, of our 
spring garden flowers, is of rather recent introduc¬ 
tion from Japan, and the Japanese got it, as is 
thought, from the north of China—a climate so like 
that of the Atlantic United States that it grows 
here as if “ to the manner born.” It came under 
its scientific baptismal name of Dicentra, meaning 
two-spurred in the vernacular, mixed up for awhile 
with an alias of Dielytra, which might mean a two- 
shelled bug, or clam, but has no appropriate mean¬ 
ing whatever for this flower in any way, and hap¬ 
pily is noiv got rid of, except in some catalogues, 
And for a popular name somebody in this country 
made a good hit when they called it Bleeding-heart. 
The flowers, especially before opening, are heart- 
shaped and red or flesh-color, and as the tall and 
queenly plant hangs out a long row of them, dang¬ 
ling along one side of a spreading branch, some 
fanciful and love-struck swain may have likened it 
to a beautiful but cruel maiden, haughtily display¬ 
ing her conquests. 
But, to come down to the flower, and to our pro¬ 
saic narrative. Here at length we have a flower 
which is sufficient unto itself, and need solicit no 
favors. Figure 1 shows it as it hangs. In the cen¬ 
ter is a slender pistil with two rows of forming 
seeds concealed within ready to be fertilized. It 
tapers into a style which ends in an enlarged and 
crested stigma (seen in the middle of figure 3). Di¬ 
rectly against and surrounding this stigma, lie six 
anthers, three on one side and three on the other. 
They are seen spread out for inspection in figure 3, 
but in the untouched flower they are all packed 
close together and in actual contact with the stigma. 
They are kept there, and everything else is seem¬ 
ingly well barred out by the tips of an inner and 
narrow spoon-shaped pair of petals, which enclose 
the pistil between them ; their two tips, the bowls 
of the spoon, put together, and united at the very 
apex only, so as to enclose a cavity which is just 
large enough to contain the stigma in the center, 
and its encircling crowd of six anthers. In the 
bud, and until full grown, the layer and also spoon- 
shaped tips of the outer pair of petals, each of 
which makes half the heart, are closed over the 
whole. But these soon separate and turn back 
(as seen in figures 1 and 2); the two inner never 
separate. But if we pull these open, even on the 
very day that the outer ones turn back, we may see 
that the anthers have not delayed to do their part; 
already they are opening and pouring out a great 
superabundance of pollen, a large part of which is 
actually in contact with the stigma, covering it on 
every side. The case is clear. Here, if anywhere, 
is self-sufficiency and self-fertilization. 
Inevitable as this conclusion appears to be, before 
we rest in it, we may as well consider one or two 
things. First, in our gardens, although it grows 
vigorously, it seeds sparingly, and often not at all. 
This is not what we should expect of a plant so 
well adapted for self-fertilization. If it depended 
on insects, its sterility as a new comer into a for¬ 
eign country might be accounted for by the absence 
of the particular insects it was accustomed to and 
dependent upon, but as a self-fertilizer, wherever 
it can grow well it ought to seed well. In the next 
place, the sacs which form the heart-end of the 
blossom, produce a little nectar, and a deep groove 
in the narrowed part of the large petals, under the 
spreading tip, forms an open channel leading into 
the cavity of the nectar-bearing sac. If we have 
read our former lessons aright, and if Nature is not 
at cross-purposes, this means that insects are in¬ 
vited to the blossom ; and over and over we have 
seen the bumble-bee accept the invitation and ex¬ 
plore the sac with its long tongue, with apparent 
satisfaction. It is not easy to believe that free 
lunches are quite devoid of ulterior object. To 
settle this, it might be worth trying the experiment 
of covering clusters of the blossoms with gauze, to 
see whether they would then set seed at all. This 
might not be very hopeful, since it seeds rarely and 
little as it is in this country. But it might be tried 
on our wild Dieentras, of which we have two in our 
cool northern W'oods, humble, but curious and ele¬ 
gant, one of them well 
known as the Dutchman’s 
Breeches, a long way off 
from Bleeding-heart in 
name and association, 
though the structure of 
the flower is essentially 
the same. That seeds 
rather freely in its na¬ 
tive woods, and D. eximia, 
a larger sort, native of 
the Alleghanies, and not 
rare in gardens, sets seed 
abundantly. It would 
be well to know if these 
would do so when insects were excluded. The 
same may be said of the wild species of Cory- 
dalis, which are on just the same plan as Bleed¬ 
ing-hearts, except in having only one sac or spur 
to the flowers, aud which seed abundantly. If 
they do so by self-fertilization (which is what they 
seem specially intended for), they would do the 
same under a gauze covering. If when so protected 
they are sterile, or sparingly fertile, then we may 
conclude that the visits of bees, which they appear 
to court, and which are often seen about these 
flowers, are somehow useful to them in the way of 
fertilization. The experiment has been tried in 
Germany. The Corydalis covered by gauze set 
very little seed ; those by their side left accessible 
to bees and the like, set seed in full abundance. 
Finally we may notice what happens when an in¬ 
sect of proper size, such as a bumble-bee, visits the 
flowers of Bleeding-hearts. Holding fast by the 
shelf formed by the spreading tip of either sac- 
shaped or spur-shaped petal, the act of exploring 
the sac brings the head of the insect forcibly against 
the central piece, formed of the two narrow, spoon¬ 
shaped petals, with barely cohering tips; these are 
pushed off to the opposite side, while the enclosed 
parts, the stamens and pistil, stand in their posi¬ 
tion, nearly as in figure 2. This, it will be seen, 
brings the bee’s head into contact with the anthers, 
covered with loose pollen, some of which adheres 
and is carried off, brings it also in contact with the 
stigma ; and so, in passing from blossom to blos¬ 
som, some of the pollen of one is conveyed to and 
deposited upon the stigma of some other. The ar¬ 
rangement which was supposed to ensure self-fer¬ 
tilization, proves after all to have cross-fertilization 
in view—at least some cross-fertilization. 
Figs. 1, 2 and 3.— flower of dicentra enlarged. 
But if its own pollen has the first and best chance 
—being early shed into the cavity, and the convey¬ 
ance being only occasional—why does not the pistil 
generally or universally get fully fertilized by the 
pollen which surrounds its stigma, leaving no 
chance for the comparatively little which may be 
brought ? First, because (as in the cases described 
in the first, second, and third articles) the stigma is 
not ready when the anthers first open ; it is only 
after the flower has been open a day or two that 
the stigma becomes moist and receptive of pollen. 
Secondly, there is good reason to think that pollen, 
in all such cases, is more efficient upon the stigma 
of another flower than its own. The grounds of 
this belief will appear hereafter. 
The flowers of peas and beans are conundrums of 
somewhat the same sort as those of Bleeding-heart. 
Let our readers, especially young readers, try their 
hand and powers of observation upon them this 
summer, and upon all other blossoms of the pulse 
family they meet with. They may find much that 
is very curious, and enjoy the gratification of find¬ 
ing it out themselves. Not to anticipate them, I 
will defer my account of these flowers until the 
close of the summer. 
To Prune or not to Prune. 
A large stone dropped into a small pool would 
not make a greater commotion than an address by 
Mr. Shirley Hibbard has caused among the garden¬ 
ers and fruit-growers of England. Mr. II. came 
out, in his usual forcible way, “dead agin” the 
pruning of fruit-trees; this lecture was regarded as 
of sufficient importance to be published by three 
horticultural journals simultaneously ; it was the 
occasion of several editorials, and as to the commu¬ 
nications it has called out, the end is not yet. The 
strange thing about it all is, not that Mr. H. should 
advocate no pruning, but the fuss and flourish it 
has caused. An English friend of ours, well versed 
in all such matters, writes us that it is “ the horti¬ 
cultural sensation of the year.” Those British hor¬ 
ticulturists who read American journals, must 
have seen that the let alone system has long had its 
advocates among our fruit-growers, and those who 
practice it too, and a paper on the impropriety of 
all pruning might be read without causing a sensa¬ 
tion in a meeting, much less in the whole country. 
We are young in horticultural matters, but we 
have long ago got by all that, and the effect upon 
the English people would look ludicrous, were 
not all concerned in such sober earnest. It takes a 
great deal of bad pruning to prevent a fruit-tree 
from bearing, and one will, if given time, make 
some returns in spite of every neglect. There are 
two extremes, the one of the French and Belgians, 
who resort to every possible device to make trees 
grow in every form and manner other than their 
natural one ; and the other of letting the tree have 
entirely its own way. Between these there is every 
gradation; Mr. Hibbard himself goes so far as to 
advise “ pulley pruning,” which is his name for 
hanging weights upon over-vigorous shoots to bend 
them, and is no pruning at all, but training. Our 
notion about the matter may be briefly given. Some 
children are ruined in health by over-study, but no 
one would recommend as a remedy that all children 
should grow up in ignorance ; yet this would be no 
more absurd than to insist that because some trees 
have been injured by pruning, the knife and saw 
should be abolished. We do not. doubt that many 
have pruned too much, and are quite sure that if 
proper pains were taken with young trees at the 
start, we could get along with very little removal of 
branches. Too often one plants an orchard, the 
trees grow as well as the conflict with the ends of 
whiffle-trees, and an occasional browsing will allow, 
after a number of years the owner thinks they 
should bear; he is told that his trees must be 
pruned before they will bear, and he, without other 
knowledge than that pruning means cutting, goes 
at them himself, or hires some jobber to do it for 
him, and if there is a large heap of brush, he thinks 
the wages have been earned. But the trees ? They 
are actually frightened into bearing a small crop, 
