Plant Skeletons in Winter
Dried-out stalks of tall weeds continue to spread seeds
Some plants have dropped all their seeds by winter's start, but the dried skeletons of the taller weeds and grasses continue to aid in the dispersal of late seeds.
The tall structures that held the flowers aloft to attract insects or catch the wind do not vanish quickly once they dry out. Still offering food and shelter for animals, especially birds, the stalks gradually lose pieces of their bodies, showing us the underlying structures in often fascinating ways.
Plants in the mustard family, for instance, put out distinctive seed pods, long and narrow, standing in ranks roughly perpendicular or at 45-degree angles to the stem. Both garlic mustard and dame’s rocket bloom in early spring and spend the next few months creating spicy, edible seeds, which ripen in midsummer. In both species, the oblong black seeds form along both sides of a membrane that runs down the center of the seed pod. When the seeds are ripe, the pod dries out, and the outer covering splits in two, pulling slightly away from the pod so the seeds can be shaken out by passing animals or breezes. By midwinter, most of the coverings have fallen away, leaving behind the central membrane, translucent and stiff, held in a narrow frame of pale brown. You can even see the tiny stems the seeds were attached to while they grew. A few of these stems may still have seeds attached, especially if the pod covering is still intact.
One of the most familiar skeletons is that of the wild carrot, or Queen Anne’s lace. After flowering, the heads curl inward into a bird’s nest configuration, sheltering the seeds as they form. Once the seeds are mature, around November, the dried nests uncurl to release them. The little spurs that protected the seeds form pretty starbursts on each of the many flower stems. Eventually the spurs break off, leaving behind a striking starburst silhouette of thin brown downward-curving stems.
Common evening primrose features clustered, inch-long, tubular seed pods that curve toward the sky, with their tips dividing into four points that curl outward around a slender central shaft. The pods are usually abundant on a given plant, growing in a candelabra arrangement up to six feet from the ground. At the end of summer, when the four-petalled yellow flowers have withered away and the seeds are forming, each green pod is tightly closed, but after it dries and turns brown, the top end splits into four parts and opens up. You may then shake out the edible seeds from the four chambers within the pod. (These seeds are the source of evening primrose oil, sold in health food stores as an antioxidant and hormone balancer.) By midwinter, many of the pods have split all the way down the sides, exposing the four chambers to the winds and birds, which help with seed dispersal.
