The Invisible Plant
Prosopanche americana lives almost its entire life underground, a perennial plant that resembles a fungus. It is a holoparasite, meaning it completely lacks chlorophyll and cannot perform photosynthesis. Instead, it derives all of its water and nutrients by attaching to the roots of other plants. This species is a specialist, primarily targeting the roots of trees in the legume family (Fabaceae), such as Prosopis species. Its entire body consists of a branching, tuber-like root system, called a rhizome, that grows unseen beneath the soil. These rhizomes have rows of small bumps which are haustoria—the specialized structures that penetrate the host's roots. The plant has no leaves or stems, and the only part that ever emerges above ground is the flower.
The plant belongs to the family Hydnoraceae, a small group of parasitic plants now placed within the order Piperales. This makes it a distant relative of black pepper. The family has a classic Gondwanan distribution, with the genus Prosopanche found in Central and South America and its relative, Hydnora, found in Africa and the Arabian Peninsula. This distribution suggests their common ancestor existed before the supercontinent Gondwana broke apart around 100 million years ago. The lineage that led to these plants is considered one of the earliest origins of parasitism in flowering plants, dating back approximately 91 million years.