Melampyrum is a genus of approximately 20 species of annual herbaceous flowering plants in the family Orobanchaceae (order Lamiales), commonly known as cow wheats. The genus is placed within Orobanchaceae, a family notable for containing many parasitic and hemiparasitic plants.
All Melampyrum species are hemiparasites: they attach to the roots of neighbouring plants and extract water and mineral nutrients from their hosts, while still retaining the capacity for photosynthesis. Some species can complete their life cycle without a host, though they grow less vigorously when doing so. This hemiparasitic habit distinguishes the genus from fully autotrophic flowering plants and links it ecologically to the vegetation communities where it grows.
The genus is native to temperate regions of the Northern Hemisphere, with species distributed across Europe, Asia, and North America. European representatives include Melampyrum pratense (common cow-wheat), Melampyrum cristatum (crested cow-wheat), Melampyrum nemorosum (wood cow-wheat), and Melampyrum sylvaticum (small cow-wheat), typically found in woodlands, heathlands, and grasslands. Asian species include Melampyrum roseum and Melampyrum koreanum, while Melampyrum lineare (narrowleaf cow-wheat) represents the genus in North America.
Melampyrum species also have ecological significance as larval food plants for certain Lepidoptera, including the mouse moth (Amphipyra tragopoginis).
Etymology
The name Melampyrum derives from the Greek melas (black) and pyros (wheat), a reference to the dark seeds of these plants, which were said to contaminate grain harvests and discolour flour when mixed with harvested wheat.
Distribution
Melampyrum is native to temperate regions of the Northern Hemisphere, with species occurring across Europe (from the British Isles to eastern Europe), Asia (including Japan, Korea, and China), and North America (primarily M. lineare across Canada and the northeastern United States).
Ecology
As hemiparasites, Melampyrum species attach via haustoria to the roots of a broad range of host plants, including grasses, sedges, and woody shrubs, extracting water and nutrients while conducting photosynthesis themselves. They grow in a variety of habitats including deciduous woodlands, heathlands, and semi-shaded grasslands. The genus plays a role as a larval food source for certain moths, including the mouse moth (Amphipyra tragopoginis).
