One-flowered Cancer-root (Orobanche uniflora), also known as One-flowered Broomrape, is now flowering in fens — wetlands similar to bogs, but less acidic and more mineral-rich. Covered with glandular hairs, its flower looks like it’s made of crystallized sugar. One plant produces up to five flowering stalks, each of which bears a single, fragrant, white-to-lavender flower.
One-flowered Cancer-root has no chlorophyll in the scale-like leaves that grow on its underground stem, and thus is incapable of making its own food. This parasitic plant is classified as a holoparasite – entirely dependent upon other host plants for its nutritional needs. A One-flowered Cancer-root seedling must find a suitable host plant (often sedums, saxifrages and asters) within a few days of germinating or die. The search for a host by One-flowered Cancer-root is guided by chemicals released by the growing roots of the host species. Once a host plant is located, the One-flowered Cancer-root’s root hairs exude an adhesive substance that attaches its roots to those of the host plant. Enzymes break down the cell walls of the host, and a tuber-like connection (haustorium) forms between the vascular tissue of the two plants, allowing the movement of water, minerals and carbohydrates to flow in one direction, from host to parasite. (Thanks to Shiela and Steve Swett for photo op.)
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