Hemiparasitic wildflower
Rhinanthus is hemiparasitic on grass which means that although it has chlorophyll and can photosynthesise, it is partially dependent on nearby plants that it is connected to. The plant is named for its seed pods which rattle when ripe.
Here I’m sticking to Rhinanthus minor: there is a similar larger flower, Greater Yellow-rattle Rhinanthus angustifolius, but it is rare in Britain.
Yellow rattle – Rhinanthus minor
This wildflower has upright flower stems to 50cm with yellow flowers. Each flower is about 1cm long with two tiny purple teeth on the top lip. The calyx is large, rounded and flattened either side of the flower. The leaves are glossy dark green and serrated. I saw it recently in long grass at Kirkby Moor nature reserve in amongst orchids, where I’m pretty confident it had been sowed.
Although Yellow rattle is a native British annual wildflower, it is commonly sown in the UK to improve wildflower meadows. Grass competes with the flowers, so reducing the grass vigour by introducing a parasitic species helps the flowers to thrive.


Rhinanthus minor at Cradle Valley Seaford

The flowers were more of an orangey colour but the purple teeth are still visible. The calyx is more papery than the ones at Kirkby Moor so I guess these are on the way to drying out, possibly explaining the purple tinge on the calyx and stem.

Narrow serrated leaves:

This papery dried seed head will rattle satisfyingly.

Rhinanthus minor has various subspecies which I don’t feel qualified to comment on!
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