Chrysosplenium species - Golden Saxifrages
There are two similar species. The C. oppositifolia is the commoner one but they often occur together.
While one difference is the arrangement of the leaves, the easier one to spot is the shape of the leaves, especially at the base.
Chrysosplenium oppositifolium - has a leaf that tapers to or cuts off at the stalk.
Chrysosplenium alternifolium - has leaves that are clearly cuneate at the base and are sometimes wider than deep so they appear almost kidney-shaped and they are also more deeply lobed.