Blue Cohosh, one of our early spring wildflowers, has diminutive flowers that open before its leaves fully expand. Like Wild Ginger, Blue Cohosh flowers are the color of rotting meat, which may account for the fact that flies are its main insect visitors. Flies tend to feed at a single flower until satiated, which is not conducive to cross-pollination, and thus most fertilization in Blue Cohosh is the result of self-pollination.
Native Americans treated a wide range of afflictions with Blue Cohosh, including gallstones, fevers, toothaches and rheumatism. The most common use of its rhizomes, or underground stems, was as an aid to speed and ease childbirth. Even today it still serves this purpose — 64% of midwives surveyed reported using Blue Cohosh to treat women before or during childbirth. It has, however, had deleterious effects on some women and has not been evaluated by the FDA.
Flowers that have limited opportunity to attract pollinating insects, such as those that mature very early in the spring, often are self-fertile – they can produce seeds without the benefit of pollinators. Wild Ginger (Asarum canadense) is a perfect example of this.
Wild Ginger has six inner stamens and six outer stamens, all of which produce pollen. In a newly-opened flower, all of these stamens lie flat against the “floor” of the flower. When the stamens are in this position, pollination is achieved by insects (often flies or beetles attracted to its rotten meat coloring and scent) as the pollen cannot reach the receptive stigma on its own. Wild Ginger hedges its bets, however. Whether or not pollination occurs early in its development, later in the life of the flower both inner and outer stamens move into an upright position, thereby moving closer to the stigma. Because the flower is oriented downward, this change in the position of the stamens allows for the pollen to fall onto the stigma, thereby accomplishing self-pollination. With or without pollinators, Wild Ginger succeeds in producing seeds.