Common Name: Yellow Rattle
Scientific Name: Rhinanthus minor
Yellow Rattle is an annual herbaceous flowering plant with vivid yellow flowers. It has distinctive leaves with a serrated margin and although it can grow up to 50cm tall, it is often much shorter. The common name refers to the rattling sound it makes when shaken when it has gone to seed, much like a baby’s rattle. However, it’s most interesting feature is that it is a hemi-parasitic species.
Habitat & Range
Yellow Rattle is found throughout the British Isles, and has a widespread distribution in Europe and North America. Although this would suggest a broad climatic tolerance, the distributions of each of the six distinct sub-species are strongly linked with climate. This plant favours grasslands with low or open vegetation, but has also been recorded in environments ranging from bogs to roadside verges.
Plants tend to become established by developing a significant root system. However, hemi-parasitic plants overcome the need for this by attaching to the roots of nearby ‘host’ plants and developing haustoria –a bridge from the water and nutrient store of the host to that of the hemi-parasite. This process of ‘stealing’ nutrients from nearby plants has led to Yellow Rattle being described as a ‘functional species’ in hay meadows, where its presence has a significant impact on the entire plant community.
Yellow Rattle increases biodiversity as it tends to attach to the roots of dominant grasses, suppressing their growth, whilst allowing the less dominant wildflowers and legumes to become established. As a result, it is commonly used as a traditional management tool in hay meadows to increase biodiversity.
The increase in forbs and legumes results in more brightly coloured flowers, which attract insects such as bees and butterflies to pollinate them. Moreover, Yellow Rattle is itself an important pollinator species. It’s not just insects that favour these flowers though; research suggests that people tend to find grasslands more appealing when there are more ‘pretty’ wildflowers compared to grasses. So, next time you’re walking through a hay meadow, look out for these small yellow flowers and think of the work they do underground that we reap the benefits of above the surface.
Naomi Rintoul, PhD
Lecturer - Canterbury Christ Church University
Naomi is a lecturer in Soil Science and Environmental Policy at Canterbury Christ Church University, England. Her research interests include soil science, plant community ecology and pollution. Having always had a keen interest in nature, she is also investigating the relationship with people and their natural environment, in particular the perception of plant biodiversity.