The Sweet Pea

Teacher’s Story

MONG the most attractive of the seeds which make up the treasure of the children’s seed packets, the sweet peas are of the prettiest. They are smooth, little white or brown globules, marked with a scar on the side, showing where they were attached to the pod. One of these peas divides readily into two sections; and after it has been soaked in water for twenty-four hours, the germ of the future plant may, with the aid of a lens, be seen within it. After planting, the sprout pushes through the seed-coat at a point very near the scar, and leaf shoots emerge from the same place; but the two act very differently. The leaf lifts upward toward the light, and the root plunges down into the soil. As the plant grows, it absorbs the food stored in the seed; but the seed remains below ground and does not lift itself into the air, as happens with the bean. The root forms many slender branches, near the tips of which may be seen the fringe of feeding roots, which take up the food and water from the soil. The first leaves of the pea seedling put forth no tendrils, but otherwise look like the later ones. The leaves grow alternately on the stalk, and they are compound, each having from three to seven leaflets. The petiole is winged, as is also the stem of the plant. There is a pair of large, clasping stipules at the base of each leaf. If we compare one of these leaves with a spray of tendrils, we can see that they resemble each other in the following points: The basal leaflets of the petiole are similar and the stipules are present in each case; but the leaflets nearest the tip are marvelously changed to little, stiff stems with a quirl at the tip of each ready to reach out and hook upon any object that offers surface to cling to. Sometimes we find a leaflet paired with a tendril. The sweet pea could not thrive without a support outside of itself.

Of course, the great upper petal of the sweet pea blossom is called the banner! It stands aloft and proclaims the sweet pea as open; but before this occurs, it tenderly enfolds all the inner part of the flower in the unopened bud, and when the flower fades it again performs this duty. The wings are also well named; for these two petals which hang like a peaked roof above the keel, seem like wings just ready to open in flight. The two lower petals are sewed together in one of Nature’s invisible seams, making a long, curved treasure chest resembling the keel of a boat, and it has thus been called. Within the keel are hidden the pistil and stamens. The ovary is long, pod-shaped and downy; from its tip the style projects, as strong as a wire, curving upwards, and covered with a brush of fine, white hairs; at the very tip of the style, and often projecting slightly from the keel, is the stigma. Around the sides and below the ovary and style, are nine stamens, their filaments broadening and uniting to make a white, silken tube about the ovary, or young pod. From the tip of this stamen-tube, each of the nine filaments disengages itself, and lying close to the style thrusts its anther up into the point of the keel, below the stigma. But strange to say, one lone, lorn stamen “flocks by itself” above the pistil, curving its anther up stigma-ward. If we touch the point of the keel with the finger, up fly—like a jack-in-the-box—the anthers splashing the finger with pollen; and if a bee, in her search for nectar, alights on the wings at the very base of the petals, up flies the pollen brush and daubs her with the yellow dust, which she may deposit on the stigma of another flower. The interesting part of this mechanism is the brush near the tip of the style below the stigma—a veritable broom, with splints all directed upward. As the pollen is discharged around it, the brush lifts it up when the keel is pressed down, and the stiff petals forming the keel, in springing back to place, scrape off the pollen and plaster it upon the visitor. But for all this elaborate mechanism, sweet peas, of all flowers, are the most difficult to cross-pollenate, since they are so likely to receive some of their own pollen during this process.

The sweet-pea bud droops, a tubular calyx with its five-pointed lobes forming a bell to protect it. Within the bud the banner petal clasps all in its protecting embrace.

After the petals fall, the young pod stands out from the calyx, the five lobes of which are recurved and remain until the pod is well grown. As the sweet pea ripens, all the moisture is lost and the pod becomes dry and hard; through the dampness of dews at night and the sun’s heat which warps it by day, finally each side of the pod suddenly coils into a spiral, flinging the seed many feet distant in different directions.