Leonard and I are planning a trip to Oregon. Naked broomrape (Orobanche uniflora) is a plant that eluded us and we were told where we might find them in Oregon.
Meanwhile, last Tuesday we returned to some scab land on Modoc National Forest Road 43N96A near Cedar Pass (Modoc County) where last year I found an interesting Carrot Family (Apiaceae) plant. Last year it was already in seed, so I wanted to return this year to see the plant in flower. There, totally unexpected, Leonard found some naked broomrape specimens. What a surprise!
Naked broomrape is a parasite on stonecrops (sedums), saxifrages and Sunflower Family (Asteraceae) members, among others. Its seeds germinate in response to compounds exuded by the host’s roots. The seedling must remain in contact with the host in order to develop. Naked broomrape has no chlorophyll and does not produce its own nutrients.
Naked broomrape has a short underground stem with highly modified, scale-like, alternate leaves. The stem becomes an underground tuber periodically producing flowers that appear unexpectedly and then disappear in other years. Thus, depending on the reference, naked broomrape may be listed as an annual or a perennial.
Only naked broomrape pedicels (flower stalks) and flowers appear above the ground. Single, yellowish white to purple flowers are borne at the tips of yellowish brown stalks, each of which is around 2 inches tall. There are one to three flowers per plant. The five petals are united into a corolla tube that is slightly bent downward in the middle. The literature describes the flower as having five spreading lobes or as having bilateral symmetry. The petal lobes are fringed with fine hairs and the corolla tubes are glandular. The four stamens are epipetalous (attached to the petals) and the superior ovary has 2 stigma lobes. The hairy sepals are united with the calyx lobes longer than the calyx tube.
Naked broomrape seeds are contained in single-chambered capsules that split lengthwise.
This native is found throughout most of North America. Its ecology is moist open sites or open woods from low to mid elevations.
The whole naked broomrape plant is edible either raw or cooked. In addition, medicinally it is a laxative and sedative. Because of its small size and the fact that it is considered an endangered species in some states, I am not certain why anyone would want to utilize this ephemeral beauty.
Naked broomrape is cross pollinated by insects, notably bees. In the absence of cross pollination, it can self pollinate.
Other common names for O uniflora are one-flowered broomrape, cancer root and ghost pipe. A synonym is Aphyllon purpureum. The genus name, Orobanche, derives from Greek – “orobas” meaning a woody legume and “anchein” meaning strangle – and refers to the parasitic nature of the plant. In Latin, uniflora, the species designation means “single flower”. There are several explanations for the colloquial appellation, broomrape. My favorite says that a British species of Orobanche is parasitic on Scotch broom and “rapes” or takes away from the host.
Even though we found naked broomrapes, the Oregon trip remains on the calendar. There are some California groundcones, another parasitic plant, that we discovered last season. They, too, were past bloom. Leonard and I need to see them in flower.