Common Name: Squawroot, Cancer-root, Bear corn, American broomrape – The colloquial term ‘squaw’ refers to a Native American woman; even though it is now largely considered to be pejorative, it is a phonetically direct derivation from the Algonquian word squa (one of many spellings). Squawroot looks like it is part of a rhizomatous system, so ‘root’ is an appropriate mnemonic suffix; however, it is a whole, flowering plant. The combination suggests that it was used in some way by Native Americans, perhaps therapeutically.
Scientific Name: Conopholis americana – The generic name is quite an appropriate assignation in that it is a combination of the Greek conos meaning ‘cone’ and pholis, meaning ‘scale’ to indicate that the plant looks like a scaled cone. The species name indicates a North American provenance.
Potpourri: The Broomrape, or Orobanchaceae, Family is comprised of about 200 species worldwide (though this number is variable according to source), primarily in northern temperate regions. The defining characteristic of the broomrapes is that they are virtually all parasitic on other plants, they have no chlorophyll and are therefore heterotrophic, relying on outside sources for nutrition (only plants are autotrophs). The etymology of both the common family name Broomrape and the scientific name Orobanchaceae are metaphorically derived from their abusive relationships with other plants.
The Latin name for the plant is Rapum genistae which translates literally as ‘turnip broom.’ Though there is some interpretative license here, the consensus opinion is that turnip is meant more as ‘turnip-like’ in that broomrapes form a large underground tuber-like extension called a haustorium that attaches to the roots of the host plant. Broom is a very common shrub in Eurasia with which broomrapes were commonly associated. As an interesting historical side note, the medieval French name for the broom was plante genista (spellings vary). This is the basis for the name of the Plantagenet Kings of England; Geoffrey of Anjou, the Plantagenet progenitor (father of Henry II, The Lion in Winter), was given this sobriquet because he frequently either wore a sprig of broom on his bonnet or he planted many broom plants on his hunting grounds in Anjou (Encyclopedia Britannica, the authority on all things British, provides both etymologies). The last Plantagenet was King Richard III, recently exhumed in Leicester. The scientific name Orobanchaceae is derived from the Greek orobos, which means ‘bitter vetch’ and anchein which means ‘strangle.’ The bitter vetch was one of the early staple food crops of the Mediterranean region; it is similar in form and function to a lentil. The pejorative implication was presumably that the orobanche plants would seek to exterminate a mainstay crop. One might conclude that this is a family of bitter vetch stranglers and broom rapists. And in a sense, it is.
The broomrapes, like the mycorrhizal fungi that they emulate, are highly evolved in their life cycle to locate and parasitize host plants. However, the mycorrhizal relationship with fungi is mutually beneficial as the plant gets minerals and a better water delivery system from the fungus in return for glucose nutrition. The broomrapes give nothing in return and are true parasites. The life cycle of the broomrape starts with the release of large numbers – in some cases on the order of 100,000 – very light, microscopic seeds with a dormant longevity of about 10 years; the similarity to fungal spores is not coincidental. The light weight of the seeds allows for wide-ranging wind dispersal and the saturating high numbers provide for the low probability of germination. Since the broomrapes do not have chlorophyll, the seeds must find food almost immediately after germination or they will wither and die. Since each broomrape plant is parasitic to certain species of host plants (squaw root is predominantly associated with oak and beech trees), they must find the correct plant before they germinate. The insidious way that they do this is to sense the chemicals exuded from the roots of the appropriate host targeted plant as a means of triggering the germination signal. This effect only extends over a very short distance so that on germination, the lower portion of the seedling axis – the radicle – needs to grow for only a short distance before it reaches the root from which its sustenance is attained. Directionality is provided by the sensors that lead the growing radical tip to chemicals of the host plant root; this is referred to as chemotropic attraction. The broomrape radicle attaches to the rootlet of the host plant and immediately parasitizes it, using the pilfered glucose to swell to a nodule on the root. The nodule, now ensured of a source of nutrition, grows and forms secondary nodules that attach to the host plant roots in multiple locations. The original hypogeal (below ground) nodule continues to grow until it is large enough to support its own epigeal (above ground) flower-bearing structure to form the seeds to complete the life cycle in perpetuity. It is not clear why the host tree allows the broomrapes to envelop its roots. It is probable that these plants, which also have beneficial mycorrhizal relationships with fungi (on which they depend), are duped by the broomrapes who emulate the fungi – a cross kingdom doppelganger.
In addition to Squawroot, there are two other broomrapes that inhabit the same range from southern Canada to the Gulf Coast along the eastern seaboard inland to the Mississippi River: Beech Drops (Epifagus virginiana) and One-Flowered Cancer Root (Orobanche uniflora). The former is parasitic only on beech trees (Fagus spp), the genus name literally means “on (epi) beech (fagus).” It looks much more like a germinating plant than Squawroot, the ramifying stalks seeming to reach upward to the light. Since there is no photosynthesis, the verisimilitude is to extend the flowers upward to provide more elevation for seed dispersal and not phototropism. The plant is initially yellowish-tan in color, changing to a more red-tinged magenta over time. The One-Flowered Cancer Root is one of the most delicate of forest flora and seems an apparition; it is also known as ghost pipe and naked broomrape as a reflection of this association. What is noteworthy is that it has no leaves, the diaphanous stem emerging from the ground nakedly unadorned. The colors range from white to lavender with no association with a specific tree; they have a number of hosts.
All of the broomrapes have at some time been used for a variety of medicinal purposes. The common name Cancer-root can be found in association with all three that are discussed herein. Native Americans generally used them internally (as a decoction) for the treatment of respiratory and bowel problems and externally as a topical agent for treating skin infections. There is also evidence of the use of broomrapes in the same general manner in Europe; the plants are noted for their astringent properties. Physicians in this country adopted these practices in the pre-pharmaceutical era of natural medicines to arrest bowel and uterine bleeding and as a poultice to treat wounds and other skin problems. It is in this latter application that the name Cancer-root likely arose – as a treatment for sarcomatous, cutaneous lesions.