Water-cress?

[NickWood]

I've had very kind help identifying fungi in the past, I wonder if you help with this flower ID?

Found on a sheltered piece of ground above a canal lock, this small plant (approx. 3cm high) has the basic features of Water-cress (Rorippa or Nasturtium officinale):
Short, with a thick purplish stem, leaves pinnate and deep glossy green, flowers white, with four petals in congested heads.
However, the plant differs from descriptions in reference texts: It is certainly not hairless (with distinctive hairs on leaves and stem), the stamens appear different from N. officinale, and it is not in or near water (the nearest water several meters below a parapet).

Perhaps this is just a stunted or early specimen, and the hairs would be lost later. I'd appreciate any thoughts.

[Simon Horsnall]

My gut reaction is a Cardamine sp. Given the small size, hairs and 4 apparent stamens, have you ruled out C. hirsuta?

[NickWood]

My gut reaction is a Cardamine sp. Given the small size, hairs and 4 apparent stamens, have you ruled out C. hirsuta?

Many thanks for the reply Simon, and for pointing to C. hirsuta, which is looking very likely. I wish I'd taken a better photo of the stamen - counting them is clearly crucial for distinguishing Cardamine sp. We live and learn!
Thanks, again, for the help - much appreciated.
Nick