Rhinanthus minor, known as yellow rattle, is a herbaceous wildflower in the genus Rhinanthus in the broomrape family. It has circumpolar distribution in Europe, Russia, western Asia, and northern North America. An annual plant, yellow rattle grows up to tall, with upright stems and opposite, simple leaves. The fruit is a dry capsule, with loose, rattling seeds.
The preferred habitat of Rhinanthus minor is dry fields or meadows; it tolerates a wide range of soil types. It flowers in the summer between May and September. It is hemiparasitic, notably on Poaceae (grasses) and Fabaceae (legumes), and farmers consider it to be a pest, as it reduces grass growth.
Yellow rattle is used to create or restore wildflower meadows, where it maintains species diversity by suppressing dominant grasses and the recycling of soil nutrients. The seed is sown thinly onto grassland from August to November—to germinate the following spring, the seeds need to remain in the soil throughout the winter months.
Description
Yellow rattle is a herbaceous annual plant that resembles the larger greater yellow rattle (Rhinanthus angustifolius). The species name is derived from Ancient Greek and means 'nose flower', which is in reference to the shape of the upper lip of the corolla. Minor means 'smaller'. It is classified in the genus Rhinanthus within the family Orobanchaceae.
According to Plants of the World Online it has four accepted subspecies:
- Rhinanthus minor subsp. calcareus – Endemic to Great Britain
- Rhinanthus minor subsp. lintonii – Endemic to Great Britain
- Rhinanthus minor subsp. minor – Native to Europe and western Asia, introduced widely
- Rhinanthus minor subsp. monticola – France, Great Britain, and Ireland
The synonyms of Rhinanthus minor and its four subspecies include 50 species names.
Distribution and ecology
thumb|upright|Yellow rattle plants with flowers and seed capsules
Rhinanthus minor is found in Europe, western Russia, western Siberia, northern USA and throughout Canada. but is a facultative parasite, in that it acts opportunistically when in contact with a root. The hemiparasitic nature of yellow rattle can result in stunted, unbranched individual specimens. The plant can associate with many different host species, notably Poaceae (grasses) and Fabaceae (legumes).
In Ireland and Scotland, yellow rattle is often associated with Machair habitat, which consists of coastal grassland. The seeds are spread effectively by traditional hay-making practices. As of 2021 a majority of studies had found positive or neutral effects of the introduction of Rhinanthus spp. on grassland species richness and diversity, with most finding a negative effect on grasses.
Conservation status
Rhinanthus minor is found in low-lying fields with poor quality soil. It is currently not under threat; as such it is rated as of Least Concern (LC).
After the yellow rattle plants have germinated and matured, the fruits shed their seeds. The meadow hay is cut and removed to encourage the growth introduced wild flowers. The seed, which is short-lived, is sown in the autumn, using seed harvested that year.