By Tom Schweich
Oh! Those common names! “Broomrape” is a terrible name, except … maybe it does not mean what we think, because English has a rich history and vocabulary derived from numerous languages. The “rape” in “broomrape” comes from the Latin "rapa" or "rapum," both meaning "turnip." Thus, "broomrape" literally refers to the root of the turnip-like plant, Brassica napus, because the root of broomrape is shaped like a turnip.
Language history aside, this parasitic plant called “Clustered Broomrape.” — Orobanche fasciculata Nutt. — is rarely seen because its inconspicuous appearance makes it difficult to spot. However, it lives in many places around Golden, from the North Golden Hogback in the north to Eagle Ridge and Kinney Run in the south. Other collections in Jefferson County include Rocky Flats and Chatfield Farms, two of the best-studied places in Colorado. State-wide, our plant is found throughout Colorado, except for the southeastern plains. The fasciculata part of the name refers to the way the flowers grow together in a bundle at the top of the root.
Clustered broomrape is completely parasitic on other plants (holoparasitic). It has no leaves to photosynthesize nutrients and must tap into the roots of other plants for both water and nutrients. Other plants we have met in this column, such as paintbrush (Castilleja integra) and bastard toadflax (Comandra umbellata ssp. pallida), are half-parasitic (hemiparasitic) because they can photosynthesize with their leaves but tap into the roots of other plants for water.
Our plant is one of two broomrapes named by Thomas Nuttall (1818) for plants he found around Fort Mandan on the Missouri River. The other is named Orobanche ludoviciana. “Ludoviciana” is a Latinization of Louisiana and refers to the Louisiana Purchase of 1803. While O. ludoviciana has been found in Boulder and Denver Counties, it has not been found in Jefferson County.
The original Fort Mandan, where the Lewis and Clark Expedition overwintered in 1804-1805 and Nuttall stayed in 1811, was located on the Missouri River near present-day Washburn, North Dakota. However, the Missouri River has changed course over time, and the original site of the fort is now believed to be underwater.
Orobanche is a Linnean (1753) generic name applied originally to three species in Europe, and two from Virginia when it was an English colony. However, recent phylogenetic work suggests that our North American Orobanche form a unique group of plants that could have their own generic name. Aphyllon Mitch. has been proposed as the generic name for the group (Schneider, 2016). So, some Colorado wildflower books (and global databases) will list our plant under its original name of Orobanche fasciculata Nutt. and others will use Aphyllon fasciculatum (Nutt.) Torr. & A. Gray. Both names are correct, the difference just represents the difference in thought by the authors of the books and databases (POWO, 2025).
References
Colorado Native Plant Society. 2025. Field Trip Calendar. https://conps.org/home/events/event-listing/
Linne´, Carl von. 1753. Species Plantarum. https://www.biodiversitylibrary.org/page/358653#page/75/
Nuttall, Thomas. 1818. The Genera of North American Plants and a catalogue of the species to the year 1817. 2 Vols.. Philadelphia: 1818. https://www.biodiversitylibrary.org/page/723812#page/59/
POWO. 2025. Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. https://powo.science.kew.org/taxon/662331-1
Schneider, Adam C. 2016. Resurrection of the genus Aphyllon for the New World broomrapes (Orobanche s.l., Orobanchaceae). Phytokeys. 75: 107-118. Date retrieved 20 October 2020, https://www.researchgate.net/publication/311550883_Resurrection_of_the_genus_Aphyllon_for_New_World_broomrapes_Orobanche_sl_Orobanchaceae/fulltext/5a20ae9e4585158865c50b3b/Resurrection-of-the-genus-Aphyllon-for-New-World-broomrapes-Orobanche-sl-Orobanchaceae.pdf
