The Bleeding Heart
For the intricate structure of this type of flower, the bleeding heart is much more easily studied than its smaller wild sisters, the Dutchman's breeches or squirrel corn; therefore it is well to study these flowers when we find them in profusion in our gardens, and the next spring we may study the wildwood species more understandingly.
The flowers of the bleeding heart are beautiful jewel-like pendants arranged along the stem according to their age; the mature flower, ready to shed its petals, is near the main stem, while the tiny unopened bud is hung at the very tip, where new buds are constantly being formed during a long season of bloom. This flower has a strange modification of its petals; the two pink outer ones, which make the heart, are really little pitchers with nectar at their bottoms, and although they hang mouth downwards the nectar does not flow out. When these outer petals are removed, we can see the inner pair placed opposite to them, the two of them close together and facing each other like two grooved ladles. Just at the mouth of the pitchers these inner petals are almost divided crosswise; and the parts that extend beyond are spoon-shaped, like the bowls of two spoons which have been pinched out so as to make a wide, flat ridge along their centers. These spoon-bowls unite at the tip, and between them they clasp the anthers and stigma. Special attention should be given to the division between the two portions of these inner petals; for it is a hinge, the workings of which are of much importance to the flower. On removing the outer petals, we find a strange framework around which the heart-shaped part of the flower seems to be modeled. These are filaments of the stamens grouped in threes on each side; the two outer ones of each group are widened into frills on the outer edge, while the central one is stiffer and narrower. At the mouth of the pitchers all these filaments unite in a tube around the style; near the stigma they split apart into six short, white, threadlike filaments, each bearing a small, brilliant yellow anther. So close together are these anthers that they are completely covered by the spoon-bowls made by the inner petals, the pollen mass being flat and disklike. During the period when the pollen is produced, the stigma is flat and immature; but after the pollen is shed, it becomes rounded into lobes ready to receive pollen from other flowers.
Although the description of the plant of this flower is most complex and elaborate, the workings of the flower are most simple. As the nectar-pitchers hang mouth down, the bee must cling to the flower while probing upward. In doing this she invariably pushes against the outside of the spoon-bowls, and the hinge at their base allows her to push them back while the mass of pollen is thrust against her body; as this hinge works both ways, she receives the pollen first on one side and then on the other, as she probes the nectar-pitchers. And perhaps the next flower she visits may have shed its pollen, and the swing door will uncover the ripe stigma ready to receive the pollen she brings.
The sepals are two little scales opposite the bases of the outer petals. Before the flower opens, the "spouts of the nectar-pitchers" are clamped up on either side of the spoon-bowls, as if to keep everything safe until the right moment comes; at first they simply spread apart, but later curve backward. The seed-pod is long and narrow, and in cross-section is seen to contain two compartments with seeds growing on every side of the partition.
The bleeding heart is a native of China, and was introduced into Europe about the middle of the last century.
Reference—Our Garden Flowers, Keeler.
The Bleeding Heart
Leading thought—The bleeding heart flower has its pollen and stigma covered by a double swing door, which the bees push back and forth when they gather the nectar.
Method—Bring a bouquet of the bleeding heart to the schoolroom, and let each pupil have a stem with its flowers in all stages. From this study, encourage them to watch these flowers when the insects are visiting them.
1. How are these flowers supported? Do they open upward or downward? Can you see the tiny sepals?
2. How many petals can you see in this flower? What is the shape of the two outer petals? How do they open? Where is the nectar developed in these petals?
3. Take off the two outer petals and study the two inner ones. What is their shape near the base? How are their parts shaped which project beyond the outer petals? What does the spoon-end of these petals cover? Can you find the hinge in these petals?
4. Where are the stamens? How many are there? Describe the shape of the stamens near the base. How are they united at the tip?
5. Where is the stigma? The style? The ovary?
6. Supposing a bee is after the nectar, where must she rest while probing for it? Can she get the nectar without pushing against the flat projecting portion of the inner petals? When she pushes these spoon-bowls back, what happens? Does she get dusted with pollen? After she leaves, does the door swing back? Suppose she visits another flower which has shed its pollen, will she carry pollen to its stigma? Does she have to work the hinged door to do this?