Striga in the context of "Scrophulariaceae"

A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All parasitic plants develop a specialized organ called the haustorium, which penetrates the host plant, connecting them to the host vasculature—either the xylem, phloem, or both. For example, plants like Striga or Rhinanthus connect only to the xylem, via xylem bridges (xylem-feeding). Alternately, plants like Cuscuta and some members of Orobanche connect to both the xylem and phloem of the host. This provides them with the ability to extract resources from the host. These resources can include water, nitrogen, carbon and/or sugars.

Parasitic plants are classified depending on the location where the parasitic plant latches onto the host (root or stem), the amount of nutrients it requires, and their photosynthetic capability. Some parasitic plants can locate their host plants by detecting volatile chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plants in approximately 20 families of flowering plants are known.

Orobanchaceae, the broomrapes, is a family of mostly parasitic plants of the order Lamiales, with about 90 genera and more than 2000 species. Many of these genera (e.g., Pedicularis, Rhinanthus, Striga) were formerly included in the family Scrophulariaceae sensu lato. With its new circumscription, Orobanchaceae forms a distinct, monophyletic family. From a phylogenetic perspective, it is defined as the largest crown clade containing Orobanche major and relatives, but neither Paulownia tomentosa nor Phryma leptostachya nor Mazus japonicus.

The Orobanchaceae are annual herbs or perennial herbs or shrubs, and most (all except Lindenbergia, Rehmannia and Triaenophora) are parasitic on the roots of other plants—either holoparasitic or hemiparasitic (fully or partly parasitic). The holoparasitic species lack chlorophyll and therefore cannot perform photosynthesis.