WAVY BITTER-CRESS

Cardamine flexuosa

Cabbage Family [Brassicaceae]

month8apr month8april month8may month8jun month8june month8jul month8july month8aug month8sep month8sept

status
statusZnative
flower
flower8white
inner
inner8cream
morph
morph8actino
petals
petalsZ4
stem
stem8round

8th April 2017, St. Helens Canal, St. Helens, Merseyside. Photo: © RWD
Has great propensity to spread like wildfire and will pop up in gardens year after year despite weeding. If you don't look for a month after weeding, more will have grown in the lawn or around the edges and in the cracks in paving! Surrounded by Stinging Nettle yet to grow taller.


22nd April 2008, Sabden, Lancashire. Photo: © RWD
The stems are not straight but zig-zag and wavy and have many pinnate stem leaves.


12th April 2009, Authors Garden, Walkden. Photo: © RWD
The stems are hairy but somewhat contradictory, those of Hairy Bitter-cress have fewer hairs apparently. (It is the leaf stalks which are usually hairy in Hairy Bitter-cress, but the stems are usually hairless).


22nd April 2008, Sabden, Lancashire. Photo: © RWD
The flowers are white, very small, between 3mm and 4mm across and with four petals. The flowers only fully open in bright sunlight, as here. The seed pods long and cylindrical and curved.


22nd April 2008, Sabden, Lancashire. Photo: © RWD
Un-like Hairy Bitter-cress which has but four stamens, this has nominally six stamens.


12th April 2009, Authors Garden, Walkden. Photo: © RWD
Stem leaves pinnate, narrow and with few teeth.


12th April 2009, Authors Garden, Walkden. Photo: © RWD
Petals splayed outwards, nominally six stamens with cream coloured pollen.


12th April 2009, Authors Garden, Walkden. Photo: © RWD
Snow-white petals. And six stamens, two of which are slightly shorter than the other 4 as per spec.


19th April 2007, Canalside, Chirk, North Wales. Photo: © RWD
Stems hairy and zig-zag with stem leaves numbering greater than four and up to 10.


8th April 2017, St. Helens Canal, St. Helens, Merseyside. Photo: © RWD
The seed pods are long and overtop the flowers although your Author thinks that that is not an identifying feature in the case of Bitter-cresses.


8th April 2017, St. Helens Canal, St. Helens, Merseyside. Photo: © RWD
The seeds can be seen at regular intervals in their pods by the slightly raised humps. Anther still attached to the pod on the right.


8th April 2017, St. Helens Canal, St. Helens, Merseyside. Photo: © RWD
Seed pods emerging from four of the flowers.


8th April 2017, St. Helens Canal, St. Helens, Merseyside. Photo: © RWD
The six stamens, the two each side are slightly lower and might be missed in a count. 6 stamens for Wavy Bitter-cress, only 4 stamens for Hairy Bitter-cress.


8th April 2017, St. Helens Canal, St. Helens, Merseyside. Photo: © RWD
Anthers with pollen. Central pale-green style in the centre will become a seed-pod when fertilised and ripe.


Easily confused with : Hairy Bitter-cress, but that has non-hairy stems, whereas Wavy Bitter-cress has hairy stems! Also, the seed-pods of Hairy Bitter-cress usually over-top the flowers, whereas in Wavy Bitter-cress the pods are usually lower than the top-most flower (but this is not a reliable indicator going by the flowers in the above photos; whereas the number of stamens is definitive). Wavy Bitter-cress has nominally six stamens whereas Hairy Bitter-cress has but four. The number of stem leaves also differs: Wavy Bitter-cress has between four and ten whereas Hairy Bitter-cress has only one to four stem leaves. Although the leaves of Wavy Bitter-cress are hairless, those of Hairy Bitter-cress only might possibly be hairy.

No relation to : Wavy St John's Wort nor to Wavyleaf Sea-Lavender [plants with similar names].

Hybridizes with :

  • Hairy Bitter-cress (Cardamine hirsuta) to produce Cardamine × zahlbruckneriana (Cardamine flexuosa × hirsuta)
  • Cuckooflower (Cardamine pratensis) to produce Cardamine × fringsii (Cardamine pratensis × flexuosa)
but luckily both of these are present in but very few locations, and are not present where the above photographs were taken.

Wavy Bitter-cress is very weedy. if you have it in your garden, you will like as not never get rid of it for good. It favours damp and disturbed ground in the shade. Not averse to mud, marshes or stream-sides and mountains. Almost, but not quite, ubiquitous throughout the UK.

But beware about using the number of stamens as the sole identifier. Wavy Bitter-cress is most likely to have 6 stamens (2 deeper down in the flower than the rest) but it can have only 5 or only 4. Likewise, Hairy Bitter-cress is most likely to have only 4 stamens, but it can have 5 or 6! Use as many other differing characteristics as possible for ID.


  Cardamine flexuosa  ⇐ Global Aspect ⇒ Brassicaceae  

Distribution
 family8Cabbage family8Brassicaceae

 BSBI maps
genus8Cardamine
Cardamine
(Bitter-cresses)

WAVY BITTER-CRESS

Cardamine flexuosa

Cabbage Family [Brassicaceae]

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