Plants of the Week #6-June 3

Almost all plants have a symbiotic "mycorrhizal" relationship with fungi in which the plant produces sugar through photosynthesis, gives up some of this sugar to a fungus, which in turn helps the plant absorb the water and minerals that it needs. This occurs through their interconnected roots and hyphal networks. Seems like a fair exchange, right? Quid pro quo at its best. But some plants are slackers. They are kind of laid back, free loaders that have taken up living off the work of other plants and giving nothing back in exchange. All take and no give! These are the parasitic plants and the following two examples are from the family Orobanchaceae, the broomrapes. Both are holoparasitic, or fully parasitic, as opposed to hemiparasitic plants like wood betony.

The first is Naked Broomrape (Orobanche uniflora) in a photo taken on May 17. What a name, huh? The "naked" part is because it has no leaves and "broomrape" is from the English "broom" which refers to a family of plants often parasitized by this plant, and Latin "rapum" which translates to a cluster of "tuber-like" roots. This is a rare plant that is listed as Special Concern in Wisconsin and Threatened in Minnesota. It was found on one of the bluff prairies that Friends of the Blufflands has been restoring. It is an annual that has no chlorophyll of its own, so it is completely dependent on its host plant for its carbohydrates and other nutrients. One of the plants it seems to like to rob are the goldenrods. This plant was growing next to a Cliff Goldenrod (Solidago sciaphilla), also a Special Concern plant in Wisconsin, which it was likely parasitizing by piercing the goldenrod roots with its own specialized roots called "haustoria".

The second parasitic plant is called American Cancer-Root (Conopholis americana). "Conopholis" is from the Greek conos for "cone" and pholis for "scale" describing the appearance as looking like a scaly pine cone. The photo was taken on May 26 in a nearby woods. Also called Bear Corn because bears love to eat it, it is a perennial that is also fully parasitic, usually on red oaks. Over a period of about 4 years, the plant lives underground and forms a large woody gall on the oak roots. Finally, after this 4 year period, the cancer root breaks the surface and blooms sometime during May or June as seen in the photo. It can live up to 13 years. And yes, it does bloom- those knobby looking projections along the sides of the spike are small flowers that produce no nectar and have no odor. They are self pollinating. Despite its name, it has no cancer causing or preventive properties.