This relatively recently discovered plant is a hybrid between Ludwigia palustris (Hampshire-purslane) and Ludwigia repens (Waterpurslane). It grows in a pond on Wimbledon common (its only known site so far) where it has to compete with Crassula aquatica (New Zealand Pygmyweed) and Myriophyllum aquaticum (Parrot's-feather). Since these latter two plants are capable of ousting any competitors it is surprising that all three can co-exist.

Ludwigia repens is a plant used in the aquarium trade so it is a possibility that this hybrid L x kentiana, assumed to be the red-stemmed pure species L. repens, has been sold as such and then thrown out to take hold in the wild.

The flowers are very small but would probably not be produced if at all until late summer.